Both can work very well. A well written article can produce extraordinary traffic from multiple channels. And forum traffic is a great and easy way to connect with your audience.
I think it all depends on what you are aiming for. Are you looking for more people to read what you have been writing, or are you looking for sales, or people to sign up for your newsletter? From my experience, it's fairly easy to get a lot of people to read an article compared to a post. A post at a forum will be read by many in just a few days, and after that, it sort of stops. An article at Ezinearticles will get indexed at Google and will get a lot of readers over time. I get more readers to my articles, but I don't get many sales or signups from my articles or my forum posts, but that's probably because my signatures usually sucks - jens -