TylerB covered most of it. The bit I would add on naughty chat roulette clones is below.
My rule for naughty chat roulette clones now is simple: check whether the sorting can be trusted on day one.
Took me about 3 weeks on the app to work out that the real question was whether the interface gets in the way.
Take that as one data point on naughty chat roulette clones rather than a verdict.