If your website is not a blog, do you have a blog added on to your forum? Do you find it hard to create content for both your website, forum, and blog at the same time? Then once you have a blog, how do you get people to read it since they're so accustomed to just going to the website?
Generally speaking, it has always been a little difficult for me to get my users to the blog side, since most users like the faster and better organization of a forum topic, than trying to use a blog to talk about a specific item.
Though, if a forum and a blog combo was launched at the same time, it would generally be easier for the users to refer to the blog, since both the blog and forum would be new to the user.
I've done a forum/blog combo in the past for sites, but I really think it's only suited for very specific forums that can clearly define the purposes of both the forum and blog. Most of the time, posting blog-like articles on the forum itself is fine and provides the same benefit as posting them on a separate blog would.
I added a blog to my forum after the forum was already established. People have bookmarked the forum and completely bypassed the homepage. And the community has not really participated in commenting on articles, even though they do get views.
I do not really find it difficult to write articles on the homepage though. You can do both an article and a thread on the same topic if you switch it up a little bit.
