In fact, so many blogs and
nofollow attribute will prevent search engine (not all, but most of them) to crawl the links. And that means, Link Building is not the effective way for SEO. Since now, i only add comments only if i think the post is interesting and make sure my comment is related to the post, and of course not short and crazy.
Still doing mass comment(spamming activity?) for SEO? me myself no! (i hate spammer like you do)