Just a very quick post about user interface design. I love Twitter from a UX point of view – particularly the “More” concept (no more paging), but I wanted to pick out something else that it seems to have pioneered – the use of hidden controls.
The Twitter interface is kept very clean by having no interaction controls (retweet, reply, etc.) visible until you mouse over a particular tweet. It’s a very simple, very neat solution to a perennial problem, and YouTube seem to have taken their lead (see screenshots below). Facebook has eschewed this approach, and has links for “Comment, Like, Add as Friend” on each post.