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Whilst I like your approach in how you turned the blog comment spam into a relevant piece of content for your target audience, any process in outing comment spammers or any other associated processes will result in a lot of wasted time. Comment spam is deployed in bulk, hitting millions of domains at once. The comments will largely be made using gmail email addresses so that the blog owner can't easily just ban the email domain from posting due to legitimate users of gmail. The entire process is automated, using scrapers, bots or other 'black-hat' software. The email addresses are widely not even maintained (real) - it is really of no bother to the creators, if the email address is added to mass marketing / email lists as whoever is employing them for mass spamming will own hundreds of thousands of email addresses with new ones being created every day. There really isn't any effective way of manually combating spam, not one that most can really justify the use of their time dealing with... Unfortunately.