the background is getting something like a community to run.
So if somebody wants to look up inputs (questions/answers/comments) by a special user, he will search for his user name.
e.g. the user is accepted as an expert for a special topic somebody maybe would like to see all (hopefully sensful) topics contributed by this user.
Unfortunately right now there is no way to do this...
so - yes - I think a search-function even for double word user names and giving answers, questions and comments would make sense
(with respect to social network ideas) (Thank you for asking ;)
hopefully I am not alone with this...