Absolutely not. That would only encourage spam like is the case with signature campaigns here with managers who do not check on their posters' posts for quality assurance. Recently this practice has become better where only a few campaign managers do not seem to care about post quality, but I know of a couple of campaigns which scream spam at me.

I agree that there needs to be an incentive for people to migrate or at least use both forums actively, but I do not think that payment for posting should be it. Perhaps a more niche topic that is not covered well in this forum could serve better or maybe a better trust system? Regardless, as it stands right now, I doubt it will be growing at a good pace.