Ask HN: Best blogging platform for multiple blogs on one site?

I would like the option to add blogs based on themes and project that have nothing to do with a my personal blog. It would be nice to have all those blog feed into one blog and be able to have specific themed blogs at different location. For example, If I create a community site for my town it would be nice to have that blog on that community web site as well as listed on my personal blog? I guess similar to what techcrunch does.