DNSBL — I'm wondering those solutions are never going to work totally well? When even Facebook gets rather many spammers, don't they. It'll be a tech race and t

DNSBL — I'm wondering those solutions are never going to work totally well? When even Facebook gets rather many spammers, don't they. It'll be a tech race and the clever spammers can continue spamming? I'm thinking the only? way to deal with clever spammers, that's really going to work, is to manually review the first N comments by each new commenter, and only approve the comments, if they add value to the blog post. Once someone has been able to add value to the blog post 3? 5? times (e.g. provided more useful info or thoughts, or asked on-topic questions whose answers = good for others to know too) — then the likelihood that that person is a spammer is maybe 0.01%, ok to auto approve his/her comments hereafter. I actually built such blog commenting software, link in my profile.