I voted blogs, since I want to offer blog service already for some time to my users. I can work out a partnership or buy yet another software, but them I'm stuck with two member databases. Not very user friendly neither. It's easy for them if they can jump from forum to blog and vice versa.
Why offering blog service? To create loyalty, make sure they always come back, to generate inbound links (SEO) and MONETIZE my forum. My site and forum is focused to women. They want easy tools, they don't want to setup complicated software.
Another example is a website in our country with a mix between regular site, forum AND blog. It drives traffic like hell, and advertisers!
