I'm not sure whether this suggestion already exists.. :p

I think it's very important to implement it as quickly as possible. Why? Obviously, to make it easier searching forums.
However, it's crucial to do it as fast as possible to prevent so many duplicate topics (by letting users search whether it already exists), which would come handy in the long run - it will not be as easy to handle many duplicates in, say, few months, when forums become even more active than they currently are.

Having said that, it's helpful to admins, users and server's disk space.