As I said in my foray into the conversation, one of the great things about writing on Web of all types is that through great content (on blogs, in press releases, through e-books, on Web sites, and in articles) the author can demonstrate thought leadership. The media may vary, but compelling ideas command readership. And when you are smart about a topic, people notice.
I've posted articles in many places (but not GoArticles.com). Like Jonathan, my stuff has appeared on MarketingProfs as well as RainToday.com and CMOMagazine.com. All generate great exposure. I'm constantly amazed at how people find my writing and the old "one thing leads to another" happens. I've had literary agents call and (paid) speaking gigs materialize. Not to mention new clients who want to work with me.
And search engines crawl all sorts of sites, so just getting your work out there makes it valuable in the form of search fodder.