Ah, seems quite harsh and might lead to most of the users leaving.
Disagree. If you are here for the proper reasons, and not because you want to spam in every part of the forum that you're able to in order to acquire a small sum of money, you have no reason to leave. Even though I'm currently part of a Signature Campaign, I've been trying to get them removed and/or get spam heavily reduced for quite some time now. This forum does not need quantity, it needs quality.
Spam is also a strong word for posting word for posting in different sections of the forum. Would you call , say Knightdk(who I believe is someone after sho who puts effort in his posts) spamming ? While I agree there are still quite a few persistent multi-account sig farmers who keep abusing campaigns like Bitmixer or Yobit for that matter, for making a small sum of money. The quality of the forum has definitely increased and is being maintained for the last few months and the ones who start spamming are soon reported.
Edit:
Since it has been repeated time and again that this forum doesn't need money, I would say the latter. I would also speculate that it is a very small group of people with an army of alts who benefit from the programs you mention.
While the forum doesn't need money from donators and such, it does need money to sustain the group of moderators, "pay" for the admins and the Global mods(who I believe have a higher "cut" from the ad revenue). As of right now, it is taking ~6 BTC to keep the forum going, per month