The groups on here will come and go. I will give you a fun example: A white single guy gets on SLS and has paid for a few months or so. He starts a group to facilitate bbc hookups and parties. He then messages everyone with a few hundred miles for his new group. He gets a few hundred responses and now has what appears to be a robust group. Knowing nothing about how to organize a party or gathering succeeds in in pulling about 8 people together for the first event. The event makes it painfully obvious that he just wanted to see bbc's up close and the situation is awkward.... Many newbies will start their own groups and they really wont go anywhere.
Many of the groups on here are pretty old and many are put up on a whim. Often times it will be a couple who hasn't had success or is tired of the same old same old at local events. They put up a new group to try and make new connections. They will often say they are new or real in the descriptions. These pop up like brush fires. Even couples who are successful with some of these groups get a bit tired of planning organizing and communicating to make the group successful. It isn't uncommon for them to just get a little weary or for life to pop up and take some time away from them.
Try and find the groups that have active posts and recent collection of new members. That way you know that the group is active. Some of these groups are invitation only and they may or may not find you.