The star icon to the left of the question is too vague to know what it means. I would like some sort of visual cue (other than hovering over it) as to what this actually does.
The Star is a commonly used visual element in a number of other places (twitter and gmail come to mind) to indicate that the question is special. It hasn't been around as long as certain other visual elements and hasn't had a chance to embed in the cultural consensus around UI elements. Even so, the phrase "my starred mails/tweets/questions" is already in use.
Twitter handles this by not showing it at all unless you're already hovering over the tweet, and then popping a tooltip immediately as you hover over it that says "favorite this tweet," and there is a 'favorites' link in the link list on the side.
Gmail doesn't bother with 'favorite' verbage, it doesn't document the starring and you access such mails from the "Starred [$StarImage]" link. More direct.
StackExchange is following the Twitter model.
As with squillman, I would adjust the text in the tooltip. Something like, "Favorite this question," to make it more clear.