Blogs vs Forums
What makes a blog different from a forum? I remember that the first time I used weblogs with students, the comments I got from some of them was 'Oh! It's a forum'. Since then I have heard this on other occasions from other students.
That got me thinking about the similarities and differences between these two tools (I won't repeat what is written elsewhere - if you want to join in a discussion about this, or read what others have written, then I'd encourage you to go to the forum at the Weblog in ELT group over at Search English) .
One of the things that was established during this discussion is the essential difference between the two: A forum exists for debate and discussion, while a blog's purpose seems to be better for personal opinion. What this means is that 1) while a blog only needs to have one voice to be a success, a forum only succeeds when it has lots of people contribute. 2) a blog needs to be updated regularly. This is not so critical for a discussion forum.
However, there seems to be a grey area. There are group blogs that thrive on discussion - a blog is a great place for topical discussion about one thing, although it's not recommendable to try and conduct several different discussions on the same page as this would be difficult to follow. This is solved by taking discussion of entries to a separate comments box, something which adds a forum-like feature to blogs.
Then there are the discussion forums which shows posts on a topic in chronological order - this is true of Search English, for example. The Guardian's The Talk does this too, and if the threads are too long it only shows the most recent postings (as a blog would do). This makes reading the entries to a thread much easier - there is nothing worse than finding a discussion forum which requires you to click on each separate post to open the messages. Fortunately, this type of forum seems to have disappeared.
The Journal's article Content Delivery in the Blogosphere talks about this too, and sides with blogs rather than forums : "blogs provide an environment that is more advanced than simple discussion forums"