Searching a datastore for related topics by keyword

Question

For example, how does StackOverflow decide other questions are similar?

When I typed in the question above and then tabbed to this memo control I saw a list of existing questions which might be the same as the one I am asking.

What technique is used to find similar questions?

Answer 1

I got an email from [email protected] on Mar 20 that mentions how it works:

the "ask a question" search is exclusively on title and will not match anything in the body. It is a mystery to me why people think it's better.

The last sentence refers to the search bar, which I've found is less useful when I'm trying to find a specific question I've already seen.