yes, Sitefinity supports multiple blogs which can be owned by one user. Here we are talking about users that have access to Sitefinity administration area.
If, however, you would like to provide the public users (visitors) of your site with ability to have blogs you would need to implement this on your own, but it is possible. Namely, we do not have this feature out of the box, but you can take advantage of Sitefinity Blogs API to implement this.
More information on Sitefinity Blogs API can be found here:
I hope you'll find this information helpful. Let us know if there is anything else we can do for you.
the Telerik team
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