'Tinder Social' is about a psychological phenomenon called Social Proof.
This is true design-driven innovation by Tinder, and reveals the teams deep understanding about it's user behaviour. Tinder now allows 'group meetups' (I'd not go so far as to call it 'group dating') - which simply means groups of people can now 'match' and go out together. Which is what people do all the time anyways! In the real world, we call it a party, a hangout or a pub crawl. This is powerful feature because humans rely on social markers to make decisions when information is scarce. Going out with someone alone doesn't come with many social markers, and that's the reason having a common friend or going to a familiar bar is reassuring on a first date. Tinder's group meetup brings social proof right into the core interaction, eliminating the awkwardness, risk, and discomfort of those one-on-one first dates, and provides a safe and fun setting for the genuinely single and interested to meet each other. In fact, safety means fun because now you can relax. Meanwhile, the others in the group can party on as friends.