Stop looking smug Firefox users. And while you're at it, Apple fans, you can wipe that smirk off your face too. Because Mozilla's admission that it's had to fix several serious flaws in Firefox, SeaMonkey and Thunderbird - and the suggestion that Firefox is attacked as often as Internet Explorer - exposes once again an inescapable technology truth: the more popular a product becomes, the more vulnerable it is.

Just because a product is safer to use, doesn't mean it's better built.

And the converse is true, of course. Microsoft products aren't (always) poorly designed from a security point of view, but they provide a much juicier target by dint of their ubiquity.

Being number two in a massive market has plenty of advantages. Apple has long played on the exclusivity and security of being dwarfed by Microsoft's mammoth market share.

Clearly Firefox Firefox remains a more secure browser than IE7 - and it's still my browser of choice. (Giving birth to tabbed browsing bought my loyalty for a good while yet.)

But if Firefox continues to grow at its current rates there may come a time when the tech-savvy web-surfer ditches Mozilla's excellent software and migrates to Opera or another smaller product.

In the crazy mixed up world of internet software, success doesn't always breed success.

Get the latest on PC security threats, reviews and downloads here

Get the latest broadband and internet news here