Facebook Help Center - The search box contains a personalized message when you’re logged in.
/via Jimmy Oliger
Tumblr - When someone you follow re-blogs someone you don’t, a mini follow button appears inline with the post.
/via Brian Jacobs
37 Signals - Blog post header text changes with size by dropping non-essential words as the browser viewport gets smaller.
/via Razvan Caliman
Facebook - The notifications icon shows a different side of the globe depending on your location.
/via Thomas Park
GitHub - Hovering over relative timestamps shows a tooltip with the absolute timestamp (UTC).
Apple - searching for colloquial or rumored product names (such as iTouch or iTablet) refers you to the appropriate products.
Kickstarter - The email sign up field proposes related email provider is it thinks you may have mistyped your email.