Since only one user managed to report it to support let’s say that it’s not a wide-used feature.
And he started even without fully diagnosing the issue, claimed to be some routing problem at first: http://forum.mikrotik.com/t/routeros7-socks-packet-to-another-gateway-not-working/152856/5
Only a week ago he managed to describe the problem properly.
And no I don’t have something against socks in particular, I have something against spammers.
Two dedicated topics (that I know of) and spamming every release topic with his broken socks is annoying.