Over the past year or two, the internet has become increasingly tailored so we see only what it thinks we want to see - which in most cases means what Google wants us to see. We investigate what's happening, and how you can prevent your web search being filtered.

Before the internet existed, our main source of news and current affairs was newspapers and TV broadcasts. We saw and read only what the editors decided we should, and our view of the world was shaped by this information. If a story was deemed too boring - let's say the African famine - it wouldn't be reported and you'd instead see coverage on something else.  

The internet and Google changed all that. There were no editors, so the information was freely available: all you had to do was search for it. However, whether you realise it or not, today's search results are personalised so you don't necessarily get the same view of the world as your friends, family and colleagues.

Algorithms and filters use data about you, such as your location, age, gender and preferences to deliver a set of results they think will you'll want to see. But is this a good thing?

In some cases, it may be exactly what you want. Social networks such as Facebook filter out the stuff you would have skipped over and let you quickly digest updates from close friends. However, since all this personalisation is largely invisible, how do you know what you're missing out on? Can an algorithm be trusted to make the right choices about which information you see?

In this feature, we'll look at exactly what's happening and explain some of the steps you can take to avoid or disable these filters.

Filtered search: Google searches

You'd be forgiven for thinking that a Google search for a particular word or phrase would return the same results regardless of who was searching for it around the world. That's far from the case, though, and rightly so. If you search for 'passport application' and you're somewhere in the UK, you'd want to find information that relates to applying for a UK passport.

You're unlikely to be interested in finding out how to obtain a passport in any other country, so Google uses information about your location to tailor its results to provide results it thinks are the most relevant.

This has been happening on a country or continent basis for years, but recently the algorithm has been updated to become a lot more personal. It isn't only your location which search engines such as Google use to filter results. Your search history, online contacts, the browser you're using and even the type of computer is factored in and, while the change in results can be subtle, they can sometimes be radically different.

Take the two results lists below as an example. Both searches were run at the same time, one in London, and one in Sydney. Although both start with the Wikipedia entry for Jim Martin (the guitarist in Faith No More), and have the same image results (in different orders, note) the rest of the results are completely different. It's clear which is the Australian search, but the UK search is oddly filled with US-based websites rather than UK-related results.

Jim's search in London

Edd's search in Sydney

You don't need to be signed in to a Google account to see personalised results, either. There's enough information about where you're based, plus search history to tailor searches, but things get even more personal when you do sign in. As we showed last month in our Ultimate Guide to Google, the firm has many services which all use the same account details. Not all are brimming with useful information, but if you use the Google+ social network, it's a different story. See also: How to use Google+

Here, Google knows as much as you choose to reveal about yourself. Whether it's information you post in status updates, links and videos you share, or photos you upload, it's relatively easy to understand what makes you tick and prioritise certain websites over others in your list of search results.

If this is all something of a revelation, you might decide to stop using Google. That's certainly one way to stop your data being used to tailor results, but the bad news is that just about every search engine does it. Yahoo and Microsoft Bing both use personalisation algorithms, although Yahoo's has an element of human input, so it's listings aren't entirely generated by machines.

The main problem is that few people realise that any filtering is taking place as it happens automatically. You won't see a warning or the option to opt out. This is the potential downfall in personalisation, as you may not be aware that you're no longer in the driving seat when it comes to what you want to see on the internet.

Some people argue that it's a form of censoring, while others - including the web's inventor Sir Tim Berners-Lee - say it can give you a twisted view of the world and can leave you isolated as the information fed to you is more and more personalised.

Filtered search: Social networks

This is especially true of Facebook, which has filtered its News Feed for a while now. As we said at the beginning, the aim is to put the information you want at your fingertips: the motives behind filtering content are largely blameless, but personalisation can still have drawbacks.

Facebook uses an algorithm called EdgeRank which decides what is and isn't shown in your News Feed. If you've used the social network for a few years you'll have noticed when EdgeRank was introduced (and likely been confused or upset by the change). Instead of a chronological list of status updates, the News Feed switched to a filtered one where 'important' updates (currently called Top stories) were prioritised and put at the top.

Facebook EdgeRank

Without getting into the technical details, the algorithm attempts to calculate what you'll want to read about. It looks at who you interact with most and puts status updates, photos, videos and links from those people high up in your News Feed. It also tries to figure out what else you'll want to see from people you don't regularly engage with, such as updates family members or brands you've 'Liked'.

This is all well and good, but it doesn't encourage you to maintain friendships with people you don't interact with regularly: they tend to disappear from view entirely so you won't see status updates when they post something and won't be prompted to get in touch with them.

To appreciate how much filtering is taking place, browse your list of friends and see how many of them appear in your News Feed. Chances are it's only a fraction of the total. Naturally, there will be some people who rarely post an update, but it should still be obvious that you're not seeing the full picture.

Filtered search: Twitter

Even Twitter has been accused of filtering with its trends, since it panders to users' obsession with what's new rather than what's important. Twitter also tailors search results in the name of making it easier to "get a sense of what's happening right now, wherever your curiosity takes you". But instead of enabling you to discover things, personalisation tends to do the opposite and can prevent you from seeing new things.

Filtering  also affects which online ads you see. It's pretty unnerving when you realise you're looking at adverts for precisely the product you looked at on Amazon a week ago. It's certainly clever advertising, but again, it means you're potentially missing out on seeing new products that you might also be interested in.

Next page: Are personalised results such a bad thing?

Filtered search: Are personalised results such a bad thing?

It's easy to have a one-sided view of content filters, and entire books have been written on the subject: Eli Pariser's The Filter Bubble for one. Eli warns in his TED talk that "algorithmic gatekeepers" can leave us isolated in a "web of one" if they mean the internet no longer connects us all together, introduces us to new ideas, new people and different perspectives.

It's true that filtering mechanisms can mean you see more and more of the same sort of content - a kind of ever-decreasing circle which reinforces your views and prejudices and limits your ability to discover new websites (which might challenge those prejudices) because they've been excluded from your search results.

However, it's important to remember that all these algorithms take your lead. They're not actively censoring content, but merely use the data on which links you click (and what you choose to ignore) to predict what you'll want to look at next time. You could argue that your level of exposure isn't any more limited because you wouldn't have clicked on certain news stories even if they were shown in a set of search results. Filters simply mimic your online behaviour.

We've already said that filtered content can be a big time saver, and this is an undeniable benefit in today's hectic world. Finding the information you're after faster is always a good thing, and Google's localised results help to ensure UK users, for example, aren't bombarded with an irrelevant list of restaurants in Birmingham, Connecticut when you type in "restaurants in Birmingham".

Also, being able to see at a glance what the people you care about are saying on Facebook without having to scroll through and manually filter the content from your 650 'friends' makes life considerably easier. It's possible to disable filtering but if you don't, it's probably a good idea to browse through your friends lists occasionally to ensure you're not ignoring anyone by accident.

If everyone saw the same search results world-wide, we'd be in a similar situation to the one where TV and newspaper editors decide what we see. Google would decide what's relevant for everyone, whereas filtered content means that different search results appear to different people. Would you rather be reading a personalised version ofa magazine which included only topics that you had expressed a preference for previously, or have the current version where the editorial team has decided what to include? There are pros and cons of both methods.

Without filtered data on the web, some argue, we would be overloaded with irrelevant information and be unable to handle it and locate what's important and relevant. On the flip side, as Pariser points out, 'important' and 'relevant' shouldn't be the only factors that algorithm designers consider. They shouldn't, for example, block content that might make you uncomfortable, challenge you or provide a point of view that's different from your own.

More important than this, of course, is that companies such as Google, Facebook and Twitter make it much more obvious that filtering is taking place, and make it easier to disable personalisation if you want to.

Filtered search: What you can do

This feature wouldn't be complete if we didn't show you how to avoid or disable filters. It isn't possible to escape personalisation entirely, but there are steps you can take:

Google

It's easy for Chrome users to get non-personalised search results. Click the Spanner icon and choose Settings. Click the Manage search engines... button and scroll right to the bottom of the list. In the box marked Add a new search engine, enter Google UK non-personalised. For keyword, enter Google UKNP (look for this in the Omnibox to ensure you're searching using this search engine). Finally, enter http://www.google.co.uk/search?pws=0&gl=uk&q=%s in the last box. This tells Google not to personalise results, but that your location is the UK so you'll still get localised results. Click the Make default button, and you'll get a 'standard' set of results next time you search.

Google non-personalised search

Google Search Plus your World

A few months ago, Google introduced 'Search plus your world' which gives you even more personalised results if you're signed into your Google+ account. Searches are accompanied by results from Google+, but you can click a button at the top-right of the browser window (the one with a globe icon) to hide personal results.

If this sounds like too much hassle, consider switching to a different search engine, such as duckduckgo.com. This doesn't filter results, but you might want to click the More button to the right of the search bar and set the region to UK, since it defaults to US.

DuckDuckGo

Facebook

Like Google, Facebook regularly changes its interface and options, but currently, there are a few things you can do to view an unfiltered (or less filtered) News Feed. At the top is a Sort link. Click it to toggle between the Top stories and Most Recent views.

This takes you only so far, though. On each post, a drop-down menu at the top right allows you to choose whether you see All updates, Most updates or Only important posts from that person. Click on a person's name to go to their Timeline. Here you can hover over the Friends button to choose which list they're in: Close friends, Acquaintances or other lists you've joined. Click Settings... under Show in News Feed to choose which types of updates appear.

Facebook updates

If you really want to see posts from every one of your friends, hover your pointer over Friends in the left-hand menu on the home page and click More. Click the Create list button and enter a name, such as Everyone. You will then have to add every one of your friends (or at least those you don't want to be filtered out of your News Feed by the EdgeRank algorithm) and click Create. It will take a while if you have hundreds of friends, but clicking on this list from the menu when you're done will show posts from everyone in the list.

Facebook custom list of friends

Other changes to make in Facebook include ensuring that your privacy settings (click the down arrow at the top-right corner of the website) are set correctly. One recent change, for example, is that friends of anyone tagged in your posts can see that post. To disable this, choose Custom, then untick the box marked Friends of those tagged. You can also limit who can see past posts.

In your profile, and in other online profiles, it's worth removing your birthday - or at least the year you were born. This information enables tracking companies to more easily identify you from others with the same name.

Avoid tracking

If you don't want to be tracked, start by enabling your browser's private mode. With Internet Explorer 8 or later, you can enable InPrivate browsing by pressing Ctrl-Shift-P. The same shortcut works in Firefox.

Google Chrome users can click the Spanner icon and choose New incognito window (or press Ctrl-Shift-N). When you browse in an incognito window, pages won't be added to your web history or search history. No cookies will be saved and pages won't leave any other traces, apart from bookmarks you save and files you download.

Bear in mind that if you sign into your Google account from an incognito page, your web searches will still be saved in your Google Web History. To stop this happening, go to google.com/history and click Turn Web History off.

Unfortunately, no browser's private mode is sufficient to stop people tracking you and seeing what you're looking at online. Even factors such as your screen resolution, browser plugins and version of Windows mean you're still leaving 'fingerprints' everywhere you go.

To defend against this, you can switch to a 'standard' browser such as Firefox, or use a smartphone browser. Disabling JavaScript is a powerful tool in preventing tracking, but it's needed to make most websites work properly.

Another option is to use Tor from torproject.org. This is a free VPN (Virtual Private Network) utility which effectively makes you anonymous online and prevents websites from identifying your real location. Tor is available for Windows and Android devices, but there's also a Tor web browser bundle which works on Windows, Mac and Linux and can run from a USB flash drive.

Cookies are a hot topic at the moment, as the new EU law (the e-privacy directive) came into force in May. Now, users must be made aware that a website uses cookies, and must accept them in order to continue using the site. Cookies can be useful, as websites will remember your preferences for things such as currency. However, they can also be used to track you, and it's a good idea to delete all your cookies from time to time.

Chrome privacy settings

In Chrome, click the Spanner icon, then Settings, then the Show advanced settings... link. Click Content Settings... in the Privacy section and you'll find all the cookie settings. Finally, click the All cookies and site data... button and then the Remove all button.
Firefox users should click the orange Firefox button, then Options, then the Privacy tab. You can click the Tell web sites I do not want to be tracked box and then the 'clear your recent history' link.

Firefox Do Not Track

In IE9, click the cog icon, then Safety and Delete Browsing History. Here you can choose what to delete, so you can keep the list of sites you've visited and just remove cookies.

Internet Explorer 9 Delete cookies

 Follow Jim Martin and @PCAdvisor on Twitter.