John Battelle highlights a fabulous widget from Searchblog.
Folks who come from search (I call them hummingbirds because they come via a very specific search, read one post, and leave) now get a box greeting them and giving them some search-driven options on the site.
This instance is clunky — far too wordy, who understands 'keywords'? — but for a user, done right, it's a winner. My first reaction was 'wow'.
Postscript: there are similar widgets out there - WordPress have one - and one of which I'm going to try out , Lijit.