Blogs on Fandom are pages written by one person that can be commented on and organized into a listing, like a typical blog found elsewhere on the internet. They are in the "User blog" namespace and can only be edited by the user who created it, or an administrator.
Blogs on Fandom wikis
Many wikis have the Blogs feature enabled, and you can find users blogging about all sorts of different things related to the subject of the wiki. Blogs can be used to prompt discussions, express opinions or get answers to questions. Before creating your first blog post on a wiki, it's a good idea to look at what other users are doing with their blogs there. Review the wiki's policies to see if there are any rules or guidelines around how blogs should be used; it's possible that some questions or conversations are better suited for the wiki's Discussions.
You should always abide by Fandom's community guidelines when interacting with other users—be respectful, helpful and assume good faith. Also remember that, if you're an admin, a user's blog should only be edited by that user. You wouldn't want anyone else making changes to what you wrote on your own blog, after all!
Blogs on Community Central
Due to an overabundance of spam, blog permissions have been restricted to moderators and higher on Community Central. You are still able to reply, but only permitted users can create and edit blogs now.
You are still free to blog on other wikis according to the rules and guidelines set forth by their administrators.
Fandom Staff Blog
Fandom staff members use their Community Central blogs as a way to talk to the whole community. Staff blog posts are linked on the navigation menu at the top of the wiki, and are also grouped into subject areas: Community News, Tips & Tricks, Founders & Admins, New Features and Contests & Giveaways.
If you're interested in following the details of how Fandom's underlying programming changes from week to week, check out the Technical Updates Category in Discussions, as the old Technical Updates blog page has been discontinued.