Doing the best I can at http://theseocat.com/
Yes I agree blog commenting is a time consuming task. But it's has worth in SEO. if you can not do that then you create your own blog and start posting on it...
1. Here's a great way to find niche blog posts with PR related to your industry. You give it a keyword and it trolls blog posts for do follow blog posts you can comment on. The trial is limited, because it only searches 50 blogs at a time. But when you use general keywords with the full version it will come back with 1,000+ results and usually from that you can get a mixture of PR1-PR5 dofollow blog posts (around 30-40) to comment on. It beats Google searching.
2. And the "Thats a great post, keep up the good work!" comments never work. Mention something about the article, keep it relevant and around 20 words. This might seem like a no brainer but you still see a lot of comments like this, and you are suprised some of them still get approved.
Blog Commenting is less time consuming because you can just copy and paste "Thank you for the info" with a link to your website every where you go. (that was a joke) In all seriousness, you read and you discuss specific points the author made, you can ask questions or whatnot. But you don't have to be right and there is not as much pressure compared to blog posting on your own blog.
(the Lord of the Rings Music is Really good)
You know, I have had a generally negative reaction to blog commenting as a backlinks builder because it has been so abused by spammers. But it may be no different than forum participation. I read a lot and learn a lot from forums and I might equally learn from following blogs. We have spammers on forums, just as there are blog spammers. I do think it's different when we add significant content. When we add value, our signature link or blog link becomes more valuable - not just for SEO but because quality attracts trust and traffic.
The real name as a speaker and not the comments of relevant ... may take time to validate your comment in the blog, since it depends on the blog owner or manager of this blog ... so if it is good practice, but no guarantee can be given.