318,000,000 for forum
395,000,000 for forums
(results in Google)
So sad that Overture doesn't differentiate singular/plural.
I'm leaning towards "forum", but my opinion on this changes. Might see what
a) sounds best and
b) decide how narrow of a topic will be discussed there. The narrower the topic, the more likely i'd stikc with the singular.
-Allan