Current top ten Lounge posts:
Supervillian match-ups?
How To Forget Someone You Loved But Never Got?
[Point Rewards] Draw My Attention 2 ...
I'm such a flake. How are you guys? XD
EVOLVE the Game
What is "Nationstate?"
Your favorite (non-video) games?
What is wrong with sharks????
Another addition for getting my trophy
Boroke a thousand
Where's my trophy?
With one obvious exception, I would argue that none of these threads 'contribute' any more than forum game posts do. And as Tan points out, at least the RP-oriented games contribute to people's writing skills, which they may end up applying to a storygame.