I'm getting ready to teach a course in the Spring on New Internet Media and had been planning to set up a class blog when a young man I know suggested there might be a more effective way via a class user group or forum. I agree, and so that while user groups actually preceded the Internet. And my class will emphasize new Internet tools, such as blogging, I do think it offers a better format.
A blog is a website, most often authored by one person, who picks the topics or posts for the blog in the form of their personal opinion. Others can then link to that person's posts or comment right there on the blog.
By comparison a user group or forum is authored by many people on a great many topics of their own selection. Forums are also set up so that the post and the replies to that post can be easily followed and responded to in the form of a thread to each topic. Blogs also have a means to track comments, but doing so becomes much more cumbersome when the comments are made not on the blog site, but elsewhere in the blogosphere.
For a more detailed discussion of the two types of media link here. Thank you, Alex. Great suggestion.