A blog is really a piece of news, or a journal, published by a specific author.
Here is a blog with a guest appearance of the word 'octagon'. By searching for 'octagon' in the top right hand menu or by a pre-configured search, blogs can be related to other pieces of content.
In Confluence, blogs are attached to spaces, not pages. Any user, if permitted by Confluence, may write blogs which other members can notice.
Confluence will even publish blogs to the internet, for anyone to read - this feature may be enabled or disabled for each user.