Well, this is my first “real” post on this blog so I figured it would be suiting to talk about the rationale behind it. The invention of the “rel=nofollow” tag was a huge set back for many in the SEO world while also easing pains on those within the blogging community. This tag makes it so that the major search engines do not recognize links within a given page as passing any link power. In effect, this makes it so that most spammers do not see a value in spamming, this is the theory anyway.
The problem behind this theory, is that the real hardcore automated spammers out there will still continue to do so, they are just now hoping either for traffic or to hit a few of the “dofollow” blogs. Think of it this way, if you were to have a comment on every single blog post on the internet, would you really care whether or not the search engines are looking at it? The traffic from this would be absolutely massive and it would have to make others take notice and link to your site anyway. The creator of WordPress himself says that the nofollow tag is not the solution to blog spam as it helped short term but then others continued anyway.
As a link builder, it is essential to seek out dofollow blogs and keep tabs on them so that you can wring out some of those all important do follow links (and blogs are viewed very highly in the eyes of a search engine). This explains the recent popularity of “dofollow blog search engines”
What is the solution? In my opinion a combination of software, social responsibility, and personal responsibility. If you haven’t noticed, this blog is “dofollow”, I have installed the Lucia’s Linky Love plugin which rewards those that continue to come back to my site and post. I feel that the way to reduce the amount of spam you deal with should be handled mostly by society and software that you use to weed through blatant spam attempts. This is done by showing your readers that unless you have reasonable comments, they will be deleted. If people look at the comments and they are all well thought out responses that took a minute or two to write, others will follow suit. As a reward for this, those that return and post several times will see that their links become regular links without the nofollow tag and those that truly take the time to contribute should be added to your blog roll.
In closing, making your blog do follow can be a blessing as it will increase traffic and the comments will pour in and as long as you tightly regulate the comments coming in, it will set the right example for future visitors/commentators. Feel free to comment below, and read my comment policy first 
James,
You did well for a first post! Well written and thought out. And I could not agree more with every word, except the ‘comments will come flowing in’ part.
I have no doubt that you will get your comments flowing in. You have a good style and will catch on to a lot of people.
Some people do not understand that they have to have good posts to get those good comments in the first place. Making their blog Dofollow does not guarantee them that.
Ronnie T. Dodger