Google's free, feature-laden, and still-evolving Gmail (sorry, Googlemail in the UK) service does more than just email. These tips and tweaks let you customise Gmail to manage and organise your files from any browser.
Get notified in your browser: Google's nifty Gmail Notifier utility sits in your system tray and checks for new mail at regular intervals. But if your system tray runneth over, and you are using Firefox, you can receive notifications right in the browser's status bar, through Doron Rosenberg's identically named Gmail Notifier add-on software.
Filter messages with custom addresses and aliases: Like any decent email system, Gmail lets you set up filters that act on incoming mail based on criteria you set up. For example, you can create a filter that stars all messages from email@example.com and forwards them to every other email account you use. Click Settings, Filters, Create a new filter, and follow the instructions. For more information on filters, click Help, and choose Filters under 'Common Mail Tasks and Features' to get a quick, complete tutorial.
Another convenient Gmail feature is its ability to use aliases. You can filter your incoming mail by adding a plus sign (+) and any extra characters (no spaces) to your address. For example, when you register with the Frostbite Falls Tribune site, submit an address similar to 'firstname.lastname@example.org'. Or provide your boss with an address like 'email@example.com'. Now, you can create filters that will label, star, archive (skipping the inbox), or forward only those incoming messages. And should the cash-starved folks at the Tribune sell your email address to marketers, you can change your filter to redirect messages addressed to 'firstname.lastname@example.org' to your Spam folder. (Note that 'email@example.com' isn't a legitimate address because Gmail requires that usernames have at least six characters.)
Bjarke Viksoe's Gmail Drive adds Gmail to Windows Explorer as a storage device, permitting you to drag-and-drop files to and from Google's servers, where they are stored as email attachments. Rahul Jonna's Gmail Space is similar, but it works as a Firefox extension that converts the browser into a file-transfer utility to shuttle documents between your hard disk and Gmail. When you create a filter that sends Gmail Space files to a specific Gmail folder (every file that Gmail Space uploads is attached to a message whose subject is prefixed with 'GSPACE'), you keep your inbox clear of your stored files automatically. Note that the current version of Gmail Space conflicts with the NoScript Firefox extension.
Preview your Gmail conversations in a bubble: Inspired by Google Maps' bubbles, current Google employee and occasional shareware author Mihai Parparita wrote a Greasemonkey script that pops up a preview of a Gmail conversation thread when you right-click it. First, install the Greasemonkey user scripting extension for Firefox. Next, visit Parparita's blog, click one of the links there that display the Conversation Preview Bubbles script, and select Install in the Greasemonkey toolbar. You can now read the threads in the Google window.