How does StackOverflow suggest related questions?

Question

Possible Duplicates:
Stackoverflow Related questions algorithm
Stackoverflow Search Algorithm

I expected the answer to my question to appear in the Related Questions after I typed it; however, ironically, it did not.

How does StackOverflow generate the list of related questions before I submit a new question? Is it using a full text feature of the database, or does it manually break down the text into keyword/phrases and do a custom search? Regardless, I suppose the better title of the question would be "How do you suggest similar text to the provided query parameter?"

Answer 1

tags probably

Answer 2

It is a mix of questions with related titles and matching tags.