You can only fight a social network with a social network.
A forum board is a different story u can still try to make ur forum into a social cmmunity, but face it... in the end it's still a forum. (IPB 4.0 will fix that I believe, all you need is the dedicated time to get past the new set of bugs that will likely be ranted about by the community and the time to customize the community even more.)
yes blog is needed it must be installed and active. If its not you will see a white page :|. I never understood IPB with that whitepage thing.
It uses the ip.blog's default trackback hook, and its own at the same time.
I'd need it to crate a form when submitting, the best ive been able to do right now was to make the pinging work only when IP.Blog is installed and enabled. So it relies on the trackback settings of IP.Blog. (Im not that good with creating separate methods rather fusing complete methds together)