The biggest reason I can see now based on current rhetoric, is that it's a trap. Once in, you can't get out, even if you want to. That doesn't even factor pri

The biggest reason I can see now based on current rhetoric, is that it's a trap. Once in, you can't get out, even if you want to. That doesn't even factor privacy or advertising or whatever, it's purely that you are attached to a specific corporation just to maintain relationships. If you want to get out: ask for contact details of those you need to communicate with and advise you are working out a workaround. There's no reason group admins and businesses can't set up a mailing or instant messenger list that doesn't depend on Facebook, G+, Slack, etc. In fact the owners of such groups and companies should be offering such things to help everyone decide, now's a good time...