I have heard that they are mostly nofollow links. Is blog commenting still a good way to get backlinks?
WP default is NO FOLLOW on blog comments. With that said, there's SOME blogs that follow their comments. Regardless of NO FOLLOW, you should focus on QUALITY comments to get trusted status and maybe guestblog. Comments = a great way to get credibility.
depends on the link attribute of the blog and the actual page that you'll put your link. If it's 'follow' and related to your page, then it'll be a good source of BLs
It's good for backlinks, just make sure you don't leave spammy comments, or it'll hurt you in the long run. Leave meaningful comments, and you'll benefit.
It's also good for building credibility. If you leave enough quality comments maybe the blog owner will let you guestblog
I used to offer a service here on DP where I delivered to people lists of dofollow blogs related to their respective niches. (This service isn't available anymore so please don't PM me about it.) The blogs were found by looking for a difference in the html of wordpress blogs that had the nofollow tag enabled and the ones that hadn't. So it is possible to get backlinks from commenting, but this must be done cleverly (comment relevant to post) & not abused to prevent the dofollow blogs from turning nofollow. Here's a list of dofollow blogs (dofollow at least at the time of the list's compilation): http://www.minterest.com/list-of-over-250-dofollow-blogs/
some blogg still has a do follow tags not all has a no follow tag and even if you comment on a no follow tag you can get some free traffic from comments so it is still a great technique in gathering back links and traffic.