Now you can find a mutual communities option if you check list of communities of any member.
» Official Word From Orkut:
Since orkut communities are all about the idea that everyone has something in common with everyone else, we’ve made it a little easier to see these shared interests. We just launched a feature I built that will show you which communities you have in common with other orkut members. To check it out, go to anyone’s orkut profile, click on the “view all” button below their communities, and then go to the new tab on this page, “mutual communities.” – read more