Avoid this plugin. It's expensive and, even after proper configuration, it does nothing.
Additionally, BuddyStream's"support" is non-existent. I've opened multiple support tickets (http://support.buddystream.net/) and emailed the developer directly (http://buddystream.net/contact/) but have received no response.
After all this, I'm convinced BuddyStream is little more than a cynical scam to collect money.
Caveat emptor indeed.