Offer Users Their Own Blog?

I’ve poked around a bit, but can’t find docs on the ability to use this program to offer users the ability to start their own blogs. I own a local portal and have had several inquiries about offering such an option and feel this would also do wonders for attracting users to our site.

Has anyone modified this program to do so? If not, could you possibly point me in the direction of such a program?

Thanks,
RJ