Digg users don't really intend on registering they are there for the news remember

. Contests are good but normally get spam like one word posts like "wuu2" "nothing u" "nothing"... etc..
Maybe a new skin about gaming and less spacious (there is a big gap between forums).
Also advertising is always good, your forum is new so don't expect it to be boom... It will take months/years for it to get 'big'

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Hope this helps.
Jac