The hot story in tech right now is “real-time,” thanks to Twitter and Facebook, so you’re going to hear a lot of noise over the next few years about “real-time” tech startups. Most of them will be useless and will flame out.

But here’s one that we think could actually be pretty cool: It’s called Hot Potato, and it launches today. The main idea: It’s an iPhone app (and Web site) designed specifically for people to chat about live events.

Specifically:

• It is for people to talk about the same concert they’re at, the same football game they’re watching (in person or on TV), the same bar they’re at, or whatever — as long as it’s a live event.
• It’s NOT for people to share vacation photos with their friends and family, as they do on Facebook.
• It’s NOT for people to describe their daily habits to complete strangers, as they do on Twitter.
• It’s NOT for people to share their location info with their friends, as they do on Foursquare or Loopt.

The idea: People want to be able to discuss events with each other that they’re all watching or participating in together. That’s not something that Twitter does well — even with hashtags, it’s a mess; and it’s definitely not something that Facebook status updates, when aggregated, do well.