If signature advertisements were as simple as clicking a box in your profile settings to activate it once you've reached the designated member level, and you received payouts based on views/clicks, that would be a pretty cool system. No more signature campaign managers. No more favoritism to alt accounts. No more war on newbie accounts. No more shit-posting.
This would be so easy to abuse it will destroy every advertisement here.
Anyone could simply create a bot to run a hundred ip every day and click his own link, inflate the number of views each topic has by orders of 10 and what is worse, that could be done with free tools even a 7yo could install and run.
The only way to prevent this would mean to turn the sig space into googleads in terms of surveillance and filters, and I don't think theymos is that keen on doing any of this.