ArticlesBase is a really excellent directory. It gets huge traffic. And the statistics it gives you are awesome, so you get a really good idea about how people are finding your articles. But it cops a bit of flack because it makes the author bio-box links nofollow.
I had read that if bloggers and webmasters use the articles, however, the links then become dofollow. I never looked into this though.
But I just did a backlink check for a site I've been promoting and discovered that one of my articles from ArticlesBase had been republished. Here's the original article, which is about doing stand-up comedy. The republished article is here.
I checked the source code and saw that the bio-box links on the republished article are dofollow. So, what I'd heard about the republished links is true. (Of course, I could have found this out simply by clicking through to the text that you cut and paste when you choose to republish an article. But I just never got around to it! So it was a nice surprise to find it out the way I did.)
It was also surprising to have that article republished because it's only been up there a few days and has had few views. So, maybe I was just a bit lucky with it.
I have done some searching on this subject before and from what I can tell a backlink is still (slightly) beneficial SEO-wise even if it's from a republished article. If this is true then it means there is some indirect SEO benefit from publishing articles at ArticlesBase, since you've got a good chance of having them republished with dofollow backlinks. (Even if there's no such benefit it's still worth it because of the exposure and clicks you get.)
UPDATE: I did some more searching on this subject. I found this forum thread, in which there is some disagreement over the issue of whether backlinks from duplicate content carry SEO weight. However, it does seem that the general feeling is that yes, they do help.
Here's another bit of evidence that I think supports this assertion: If I Google some of the keywords in the article, then I get both locations for it, ArticlesBase and Articles Reloaded. So, even though it's not original, it's still been indexed (and quite quickly). Also, the main URL of this directory has a PR of 0. So it's certainly "on the map" in a search engine sense. Which is why I suspect that it would have to pass on a little bit of "SEO juice".