Well yes you're right, you will also get questions with "houndoom" in them from other users. But it will be a mix, including some questions from the users houndoom or houndoom123. So if you search that way for a user you will probably find them easier.
The software for the Q&A is an external one written by someone else (although I help out a lot with suggestions etc). I think a user and tag search is still a good idea though, so I will suggest it, maybe we can add it soon.