Ask HN: Seeking advice wrt dating service and legal pitfalls

I’m building a dating/new friends service; there are numerous and diverse potential legal pitfalls, what are they and how do I protect myself and my users? For those of you with experience building such a site, or any kind of social network, what unexpected difficulties did you encounter, and did any of those arise because of technical issues (or implementation)?

What are your age and identity-verification recommendations, any nice APIs out there? Since this will be a free service, ideally, I’d like to avoid credit card-based verification as you lose potential users who refuse to give their card even if it won’t be charged (or a refunded charge).

I have implemented account activation by SMS; there are few anonymous numbers in my launch-country, and registration at launch (and a pre-launch campaign) will be restricted to numbers with this country’s call prefix. I have noticed the only verification Tinder does is Facebook and SMS activation.

Any general advice?