Nothing new here... move along, please
So the 'Fox will have a 'porn mode' to "...help you make sure that your web browsing activities don't leave any trace on your own computer" and IE8 will have a feature to "... switch off cookies, browsing and search history, (not) save form data and passwords (and) automatically clear the cache at the end of the browser session"
We've got these already: look in Tools --> Clear Private Data. I set the browser to clear private data when I close a session and the options are set to clear browsing history, download history, form and search history, cache, cookies and authenticated sessions. Additionally, I've set history at 0 days and cache at 0MB.
I also have Stephen Gould's little programme CleanUp! installed and I run it between every browser session - it empties recycle bins, deletes newsgroup caches, clears all cookies, deletes all prefetches, clears temporary internet files (in IE), and can also get shot of favourites, temp files and specified registry entries. I recommended (usual disclaimers) this utility and you can find it at
Of course, none of those precautions mean anonymous browsing; they can't stop your ISP or visited sites logging your IP address. If you want to browse anonymously (or, rather, semi-anonymously) you need to use Tor or a service like AnonyMouse:
Nor will those precautions prevent your browser leaking info about you in headers - for that you need something like the Firefox Modify Headers extention:
Has Firefox really got 20% market saturation? Who knows. My browser header's user-agent string has been modified to disguise my OS and browser type - why offer the bad guys useful info - and I know many Opera and Fox users set their user-agent to spoof IE (in fact, identifying itself as IE used to be the default option in Opera).
Nonetheless, I hope it's true - Microsoft deserves to face proper competition. Competition benefits us all - for instance, Microsoft lumbered on happily with the increasingly outdated IE6 until the Fox started grabbing market share.