I’ve seen a TON of different location-based apps in the past two weeks. But today I was introduced to one that actually is useful AT SXSW: LocalMind. What does it do? It lets you ask questions of people who are around town. “Are they still serving free beer?” you might ask, for instance. Back comes an answer.

Here founder Lenny Rachitsky showing it to me in the hallway.

What caught my eye about this? It’s like Quora and Foursquare got together and had a baby.

It shows you people who have checked in with Foursquare and have LocalMind open near you, in the past few minutes, and then you can ask them questions. Right now I’m using it and there’s dozens of different venues with people checked in right now at them. I can ask them questions, like, “how long is the line for the Mashable party?” and get an answer back right away.

After SXSW I can see asking things like “who is playing at the Ritz bar tonight?” or “how crowded is it at the Metreon?”

They have a web version, although the iPhone version is nicer.

Do you have a hot app at SXSW? Text me at +1-425-205-1921