A location within a member's group where he/she and other authors can distribute news or write commentary on a specific topic or expertise. Readers of the content can often comment on the content.
A blog is an authoritative voice in the community. A blogger (or team of bloggers) distributes information in a blog post to an audience who's involved with the post subject matter. Blogs are best suited to providing announcements, news, experience accounts or expert opinions on the subject of the blog. They and their data are tied to the group where the blog is located.
How is a blog different from a forum or gallery?
A blog is about distributing focused information. The only exchange with readers is in the comment section, and the comments are not considered as important as the blog post. A blog is most appropriate when you want to talk about experience, news, or information from a point of view. In a forum, both Q&A and discussion posts can be allowed, and the respondents are as important as this the askers. In a gallery, you're providing files to view or download.