This is enforced through filter technology, and a team of moderators.
And whilst sexual content has virtually been eradicated from the site, this also means the ratio of girls to guys has greatly improved (about 25% of users are girls). Used to be quite good, but now has a very confusing and spammy interface French site.
You WILL be removed if you are caught to be underage.
Explicit and sexual content is encouraged to be held in private chat only.
All the chatrooms, including private messages, are intended for those considered to be an adult (which specifically means ages 18 and older).