did anyone check out http://www.macrumors.com/ ? That is what I had in mind when i made this post.
It is blog style. New items, where you can comment on it. Like wordpress.
But, you click the comment button, and you get taken to a forum.
This is a high traffic site, with 73,570 threads, 870,666 posts, and 35,947 73,570 members. This amount of people/posts is hard to put into blog comments. People come for the news and info, but they really stay for the discussions and debate. There are often several pages of posts, with uploaded images, user avatars, a great search engine, and a way for like minded people to discuss other topics.
On a blog, people comment on specific posts, but without going off topic it is hard for people to discuss an unrelated issue. Forums, allow a community of like minded individuals to discuss various topics.
Also, for anyone that makes sites, your own content can only come so quick, but the site viewers are happy to create free content all day and spend their waking life posting comments and actually contributing content. Whenever you come to the site, something is new, with many new comments to read. It is a great way to keep people coming back to your site, and allowing them to browse forums/content.
Sure, you could have a blog, AND a forum on your site, but then there is 2 separate registrations, and 2 separate places to talk, and on the blog comments, no way to upload images, etc.
On some sites, the focus is on the posts and content, but on other sites, my favourite sites, the comments are more interesting and insightful than the original post. Brilliant people come together and discuss something in a way that really illuminates the topic.