Since it's been stated above here in a quote of one of Theymos' posts that he's ruled out this idea already.
I could only offer two additional suggestions (I've been skimming this thread so it's possible these have already been mentioned).
However:
• Charge campaign runners to run campaigns here (as charging for signatures seems a bit rediculous IMO as some people might just want to put random stuff below their posts to advertise their services, and if we charge for signatures then do we also charge for a personal message and avatar - like my bitcoin address that I have left there?)
• Issue fines for BOTH or Either campaign managers or signature campaign owners for running campaigns that just support bad posting quality. I don't mean, one user posts with a low quality, I mean that the entire member of a campaign continues to get posts deleted by moderators (like more than 5 or 10%). This money could then be donated to the moderators for the job that they do to help clear up the forum and to theymos and his developer teem to keep new ideas like the merit system flowing.
2) Because of the above reason , a lot of new members keep joining the forum in the hope of getting accepted. They also make posts here and all this results in forum getting traffic. Indirectly, these members are also helping forum and are responsible for the advertisement slots being sold here.
Also, more members getting involved in Bitcoin increases the acceptance of the currency as a thing and also pushes the price up a bit.
So many members discussing Bitcoin shows that the currency has a user-base behind it and that it's potentially worth its value as it is.
And it helps with the delocalisation of the currency and if more peopole have a small amount, it becomes more valuable as it's split across more people.