robdwoods - 10:28 pm on Feb 28, 2011 (gmt 0)

I have to assume this is like any other volume spam technique. If the cost is low enough even a 0.001% conversion rate can provide a positive ROI. I'd never buy Viagra from an email, or send money to someone in Nigeria, but there must be enough who do to keep sending the emails. It's the same for this. Send enough emails and you'll hit someone who's been doing SEO for 3 days and doesn't know better yet.