I’m sad to say that following some research done just now I’ve found out that posting comments on other people blogs, (specifically blogs powered by wordpress) just so you can have a link back to your own site is kinda useless. Well on most WordPress blogs at least.
I’ve been doing a bit of this myself recently and I think its been a bit of a waste of time. By default, wordpress seems to set all external links in comments as ‘nofollow’ links which means that most of the search engines including google will either not follow the links at all or if they do they wont index the linked to pages/sites.
Most wordpress blogs and sites ask for your name, email and web address when you post a comment and when the comment goes live the personal name that you put in becomes a link to your site and links to your site are great, the more the better but the search engines just wont take notice! The link can still be followed manually by other visitors to the blog so by all means continue to comment on other blogs but if you want to be noticed by the search engines then try to get links on non-wordpress sites or sites that don’t use nofollow.
Pingbacks and trackbacks seem to be treated the same way so these are pointless from a search engine point of view too.
*TIP – if you use the firefox or internet explorer browsers, theres a great SEO plugin called SEO QUAKE that will tell you whether a site or ‘Links page’ uses nofollow.
Fo more info on ‘nofollow’ see HERE.