I'm not actually sure of the official term, but I call it comment spam and I like to do it whenever I am bored of regular work. It is easy to do while talking to someone or listening to music. There are 2 key things you accomplish with comment spam: Informing a web maven about your site and hopefully improving seo through anchor text.
Comment spam is done by searching blogs for relevant content and then commenting with an anchor text link back to your site. I prefer to pre-write my comment and just copy and paste it on each blog I find. My anchor text is "math games" for hoodamath, and I think this is one of many ways you can go after seo, whether blogs are follow or no-follow.
At the very least you have informed one more person about your site, and that person/blogger is more important than someone via email spam, because they are a maven of their subject spreading news about math or education in my case, and with a little luck they will mention my site in their blog or at least approve my comment. Good Luck and let us know how it goes for you.