What's the difference between blogs and forums?

Blogs are made by the owner of the blog and other bloggers are able to contribute with comments, the owner of the blog is able to delete comments and has full control of the blog. Whereas in forums anyone in the community can contribute with posts and comments. People tend to post many short messages inside forums, while blogs are more used for posting longer messages and is more like a journal. Bloggers can follow eachother if they want to read new posts on a specific blog whereas on forums messages get lost in the stream of others messages, making it hard to follow the story.