Adding your site to different blog directories can easily increase your blog traffic. It is a good way to get links to your site, and for people to see information on your site. While Blog Directories that focus on the topic of your blog will probably bring more traffic, any Blog Directory is better than no Blog Directory.
I have found some Blog Directories to be good, and some not so. PFBlogs.com provides me with the best amount of traffic. I usually get about 5 visits per post. As opposed to PFBlogs.org, where I have gotten less than 5 visits in my last 10 posts. The other directories I belong to only bring 2 or 3 visits a week, but I keep those up there for the rankings mainly. But remember, 2 or 3 visits a week is better than nothing.
Traffic is all about getting your site out to a number of different places. It is also about getting your link in front of as many different faces as possible. Any kind of Link Directory will do this.
The reason that Pfblogs.com sends more traffic is because there are fewer blogs listed. Therefore, when you post, it stays at the top of the heap a little longer. There was a bit of a backlash from pfblogs.com since they run ads, but I don’t see any reason that they shouldn’t make a little off of it. I guarantee pfblogs.org makes a lot more than they do without their ads.