I mean anything involving us learning of their existence. Receiving messages from, observing from far away, actually coming into physical contact with, or anything else that would mean they exist.

So I guess the question is whether we'll find out there's intelligent life elsewhere in the universe, and specifically whether we'll do so within a certain time frame (such as a century).

This seems like a good example of what Yvain is looking for because there's no common political or social signaling incentive (right?), it seems pretty up in the air, it's sort of a fun question for most people, it's common, etc.