Blogs and discussion forums share a number of features and seemingly serve the same purpose, but there are some differences between them that come about from their distinct intended purposes.
The blog is what's known as a "one-to-many" communication platform, and it is specialized for that role. Blogs are designed to let group admins (i.e., teachers) communicate what's on their mind to the rest of the group members. The feedback options on a blog - the comments section - are fairly limited, because the focus is on the admin's message.
Some of the key features of a blog are:
- Limited posting rights: Only group admins can create blog posts. Group members may comment on posts, if the admin allows it.
- Only one blog per group: Because the blog is the exclusive domain of the group admins, a group can only ever have one blog tab.
- Comments are in chronological order: The comments section of a blog post is not conducive to back-and-forth conversations; this is by design, as the blog posts themselves are intended to take priority.
In contrast with the blog, the discussion forum is a "many-to-many" platform. Instead of having one person or a small group of admins running the show, discussion forums give every group member a chance to participate equally in an ongoing conversation. In light of this, the differences between blogs and forums make more sense. Guests of group spaces are not able to see discussion boards.
- Permissive posting: All group members can post to a discussion forum. Additionally, the identity of each poster is much more prominent in a forum comment than on a blog comment. Finally, students can be granted permission to post their own discussion topics, rather than having new posts come only from the teacher.
- Private replies: Individual users can mark their discussion comments "private," so that they are only visible to the poster and the person they're replying to. (Note: Group admins can also see the contents of private replies.)
- Multiple discussion forum topics: Group administrators can create as many discussion forums as they like, and members can participate in all of them concurrently. Instead of the admin making a single post at a time, users can join in multiple conversations.
- Threaded replies: "Threaded" replies allow users to respond to one another in branching sub-topics, instead of just listing comments in chronological order. This way, if a user visits a forum with six posts and wants to reply to comment #2, they can do that and their message will appear directly under that comment rather than down underneath four additional posts. This makes it much easier for multiple users to sustain a complex conversation.
- Sharing discussion boards: In keeping with the open, multi-user approach taken by discussion boards, individual discussion topics can be shared among different classes.