Forum posting is easier, but use blog commenting and other link building techniques also, so that link building looks natural. If you use only one technique it may look unnatural and Google may not like it.
I like blog commenting because it just our view on a general topic where in forum it just required a knowledge.
Blog commenting on Higher PR will have great impact on your SERPS. Links from forums will have less effect.
Forum Posting > Blog commenting Why? because you can always change your links in your signatures. Also you can put 5+ links in your signature, thus deep linking comes into play.
Try doing both. If you prefer only one, then blog comments on high PR sites will somehow do the trick.
i prefer to use commenting on related topic as many as possible some said this method is good news about our site to google
Completely agree with all of you guys. but the most thing is that to get traffic you need to be always active either on forums or blog comments. If the thread of comment is gone below or on second page you won't get the expected traffic.
Yeah, blog commenting and forum posting is the two best methods to increase back links and get more traffic. I got more back link through it.
Also, today i came across a forum on which people were saying that only dofollow blog are worth to comment and nofollow are ineffective. Let me clear it that if dofollow can give you the backlinks then nofollow blog comments can provide you the traffic benefit. Both the blogs are worth to comments and are still effective.
I find forums easier and more interesting. Blogs generally have too much text for my liking and I am too busy to read it all unless it is very interesting or relevant to me.
Even in my opinion, forums are the easiest and more interesting as they are much quickly updated with new information from the members. Also, there are so many new and different topics are posted which tells you the current position of the market.