Re: Comments won't display on main blog
This doesn’t sound like a BuddyPress issue.
It’s a WPMU issue; to be more specific, it’s a theme issue.
Do you want to show a link to comments or do you want to show actual comments?
There are number of ways to do this… theme hacking or adding a widget which displays the latest comments.
Adding a widget would be the simplest, but it depends on what you want to do.