Site that don't use rel="nofollow" in their links. So a dofollow blog is where when you comment you get a real link that transfers PR to your page.
I may get slammed for this. That's okay. There really is no such thing as dofollow. Google follows what it wants to. You cannot force google to follow a link. So many people think if a link does not use the "nofollow" tag then google follows it. Not true. Google picks and chooses what it will "follow." But even nofollow is misleading. It does not mean no follow, it means the PR juice of the site is not passed along to the link. That's it. Nothing to do with indexing or crawling. So a "do follow" link, that is without the nofollow, really is like saying, "please google, will you count this link?" They will either answer yes, no, or wait. Stephen C
Even though Google does what it wants, we mere mortals still have to play the odds and it makes sense to spend time and effort as wisely as possible by focusing on "do follow" sites to build links on.
I would have to agree with you on this point. From my own observation of different sites I seem to find that the nofollow doesn't really matter that much. Google IMO still will pick up a link even if it's nofollow. Also these so called nofollow links can help get some sites indexed, so I'm not 100% sure if it's actually a no follow.
As noted above DoFollow websites will be indexed by google and will give you a backlink. NoFollow websites will not give you a backlink. Also, you can use a NoFollow code to keep google from indexing your website.