I didn't know it was the most active but your question is a little bit provocative. Of course it wouldn't be the same at all, I'm dreaming of a Tiwer Ivory of Gambling where signatures wouldn't be displayed to let real gamblers having interesting discussions without this huge amount of spam of non-gamblers.
Participants of these gambling signature campaign are also curious about that site so most probably, they can be a potential gambler as well and this is why some gambling signature pays their hunter through their site to encourage them to try the site and have some bets. Signature campaign has a big impact