I see what you mean now. You're right, it doesn't auto correct BUT that's the way it's intended to be. Why? Think about all those crazy addresses the Net goes by these days. Your phone will go bonkers trying to correct those weird sentences and abbreviations and you'll go nuts having to re-write every time your keyboard changes "att.com" for "at. Com" or "showmethemoney.co.uk" for "Show me the money. Cow".
It does, however, show you suggestions next to the word you're typing, but it doesn't automatically change it, you have to select the correction/prediction. I actually agree with the way that's handled for web addresses.