Something which (probably) only tech-heads like me know is that Web on S60 phones is based on exactly the same 'Webkit' core code as Safari on the Apple iPhone. The reason why this is interesting is that the relative popularity of the iPhone (in the USA at least) has meant a lot of direct support on mainstream web servers. So, for example, there's a dedicated iPhone interface for Facebook, designed around the iPhone's largish touchscreen. Although it has been possible for months to access this on S60 phones, the lack of touch has meant that this mobile version hasn't been useable.
However, now that the 5800 XpressMusic has touch as well, this means that you can enjoy the full iPhone Facebook experience but on an S60 phone for the first time.
On your Nokia 5800, go to iphone.facebook.com - by default Web will show the site zoomed out, with the page's AJAX code dynamically rescaling the page elements to fit.
Don't panic though - you don't need 20:20 vision. Just double-tap anywhere on the screen and Web will zoom right in - and this is the vital bit, the iPhone-ified AJAX version of Facebook scales its page elements again, but this time to your zoomed in screen - and hey presto, the site's fully readable.
You can now use the tabs and functions and will even see iPhone-like swoops from one page to another, as you use Facebook for real, sorting out your status, your friends and your Inbox.
Enjoy!
Steve Litchfield, All About Symbian, 14 Feb 2009