Install CB Blogs then configure it as needed. It has no commenting feature, but it's all managed from their profile. If you set it to use Joomla for its storage then you can use Joomla content extensions to add commenting to blogs or other features to them. To configure it for Joomla you'll need to do the following.

1. Create a Joomla top level Section or Category
2. Add child categories to that top level Section or Category
3. Navigate to CB Blogs > Config > Model and select Joomla
4. Navigate to CB Blogs > Config > CMS and select your top level Section or Category

With the above performed you'll be ready to use CB Blogs which will store all blog entries to Joomla instead of an internal database. Simply navigate to your profile and use the Blogs tab.

An example of how your Joomla categories should be setup as follows.

Blogs <- top level category
- General <- selectable blog categories
- Games
- Movies
- Sports