Blogs are web logs; online dairies in other words. There are different platforms for it, but wordpress is totally dominating the market. One of the main reasons why blogs are so popular is because web developers started to develop blogs for themselves, which is why wordpress is one of the few free scripts out there that is actually good.
An important element of blogs is their usability; it is actually as easy as using a word document. On top of that they have all kinds of automated functions that help them to grow, like pings and trackbacks, which help to get links.
Then we get to the comments; although the blog owner can shut off the comments, they’re an essential part of a blog, especially for the success of blogs. After all Google still loves content; lots of content. And comments are extraordinary helpful, as it doesn’t cost the blog owner anything; somebody else is creating content on their blog for free; that’s good.
So that is basically the deal; you give them content and in return you get a link. But now we come to the problem; wordpress has installed a nofollow by default on all comment links, which is a horrible mistake on their side, but obviously they do not care, as it is still installed. A nofollow means just that; it a message to Google to say that the blog does not acknowledge the site it’s linking to; it distance itself from your site. Which is very selfish; they take your content which helps them and in return they tell Google that your site sucks. WordPress really does not get that.
Because of that only a very, very few blogs have dofollow links (about 0.2 %!!). That means that the blog owner has consciously installed an extra plugin to give you a real link.
It is all a matter of perception of course, while on one hand it so incredible unfair, short minded and selfish, almost criminal of wordpress to install a nofollow on all comment links; on the other hand; that is why most comments are wasted and why it is possible to make a huge difference by searching for the 0.2% of blogs that do not cheat on you with nofollow links, so you get those valuable links, there were your competition is not getting them.
This being said; the most important element to start with is to research for blogs that are first and foremost related to your site and then of course to select those few that actually give you a dofollow link. It is basically impossible to do so without using a specialized program because 99.8% of blogs use the nofollow tag. I wish I could give you a link for it, but I’m not allowed to so, but ok, I’m sure you know how to use Google to find it yourself.
Once you have your list of blogs that suits your site you can start commenting, but never forget that there’s a human being behind that blog. High quality blogs do not fall out of the sky, they have been created by somebody who has put a lot of time and effort in it; respect that. Make sure you actually read the blog, do some research if needed before you start writing and take part in the conversation, don’t just drop some BS in there; you will only end up in spam filters and once that happens it is game over!
1 little practical advice I can give you is to write your comment first in a word document, so you can do a little spell check on it, but even more so; to keep a copy. Many times something might go wrong when you submit and if so you lose the comment and have to write it again.
Although in theory you should get links from as many different IP’s as possible, there are 2 good reasons to keep using the same blog for many comments;
1) There are just not that many really good blogs out there that give dofollow links
2) As long we’re talking about quality blogs, they most likely have hundreds, perhaps even thousands of pages, so to have 10-20 or even 50 links from the same blog is just fine.
In other words, as long you take the research serious and start with a good list of blogs, blog commenting is a very effective way to get quality links and even direct traffic. While reading those posts, assuming you did your homework and you’re writing them in blogs related to your site; it’s something you should do anyway to stay in touch with your market.