I have activated the Blogs module. This gives every user a blog that they can use for their own purposes.
To create a blog entry, look in the left sidebar for Navigation. Under Add content, click on Blog entry.
Blog entries are visible to the general public by default. You can make a particular blog entry visible to only some classes of people. While you're editing a blog entry, click on the Grants tab a the top of the window. This will give you choices for narrowing visibility. (If you're confused, email me at donsakers@gmail.com.)