Safari no longer displays the contents of <title> anywhere except when viewing multiple tabs.
You can no longer tweet or update Facebook status from the notification center. The only "native" method to do this is now through Siri, which is unfortunate.
You can also tweet from Safari if your intent is to post a link to the current URI.
Unsurprisingly, icons for websites saved to the home screen no longer have the gloss effect applied.
Happy to report that iBooks is as skeuomorphic as ever.