Rather than hunting them down, I would really like to see two things implemented:
a) (this was also LoyceV idea, I think!?) an automated system where you either
- lose 1 merit for every 100 or whatever activity if you wear a signature for even a second during an activity period
- you need at least one merit in the last x days to keep your signature active
"a" is much better than "b" for reducing spammy posts made by ICO bounties. Say; every 100/75/50 posts(I would prefer 50 posts), 1 merit is reduced. But this kind of method should only be applicable to people who wear "bounty" ICO signatures.
I didn't choose "b" because there are people with default merits who wear signature that aren't ICO related like this one:

IMO, ICO bounties are the reason why people see spamfest posts on every section.
If theymos wants to gamify the new forum software, if ever it comes, method "a" is the best option.
No for deMerits, BTW.