Is there no existing version for this problem?

Idea A:
New user start with a point account of 100 shells (better as points?).
When he post, he get for every word a shell (or with an multiplier). For every participation at a poll the same (with an other multiplier).
When he get a good validation from a other user he get shells and when he make a validation for a other user he lost shells.

Idea B: (simple)
A new button under every post. A user can bit this and some shells where added to the profil of poster.