Omegle

Omegle connects you with random, anonymous strangers for a private, real-time chat under the pseudonyms « You » and « Stranger ». It requires no registration.

You may also sort strangers by common interests.

Features and modes :

✔ 1-on-1, or ask/answer question mode (see below*).
✔ Matching Language & common interests.
✔ Notifications.

* Gives you and a stranger a random question to discuss. The question is submitted by a third stranger who can watch the conversation, but can't join in.