You have to write things that people want to respond to. It's a blogging site- don't expect responses. The forum is just another aspect of it. Also, if you write tons of articles within a very short time, you won't get many responses. You are better off keeping it to one a day so that people actually see them and don't think that you are flooding the forum.
But, in the end, you can't force people to comment. If you don't write about what they are interested in, then they won't comment. As an example- I write reviews on Photography stuff. I hardly get any replies to them. But, if I write articles on a more general topic, I'll get replies. It's not the "site", it's what you write.