If I am in the OnDemand ServiceDesk Forum and want to search to see if someone else has already posted something pertaining to the same topic, when I type in the Search field, it searches through every forum for all the products and not just OnDemand ServiceDesk. This usually creates even more items to try and filter through. This sort of defeats the purpose of having the search field.
Since your subforum list is very generic (i.e. Announcements, Feature Requests, General), it might be very beneficial if your forum search would only search items within the Forum you are in.