Collarme.com
From BDSM Wiki
Collarme.com was the self described as "The Largest BDSM Community on the Planet" and was primarily a dating site that features profiles, chat, video chat, and more, and unlike it's many competitors, allowed free membership, communications and associations.
Collarme.com disbanded in 2014 after many years serving the kink community and was later reformed that same year as collarspace.com