I prefer blogs. blogs are easier to manage... don't login to your blog for 10 days and not much will change. don't login to your forum for 10 days and it will be a big mess. blogs have a lot of content on the strongest page - the home page. this gives them an advantage in SERPs over forums, where content is 1,2 or 3 clicks away from the home page. spam on blogs is easier to manage....Akismet does the job well for Wordpress. blogs also have better CTR compared to forums. forums have lot of UGC (user generated content) and in the long-term, forums can be as profitable as blogs. once you get a few good forum members and good moderator, its money on the autopilot....