Keyword spotting
Lots of buzz about using SR technology to pick up keywords in an audio stream. See Robert Scoble's demo of Nexidia or this post by Eduardo Olvera. The basic idea has been around for years, especially if you believe the NSA has been listening in on phone conversations. Even back in the Cold War, there was a demand for systems that could listen to a zillion Russian-language phone calls and alert a human analyst every time somebody said a magic word. It's also not that hard, and I like it because it's an example of an application that still works even though the technology isn't perfect.
What's hard is figuring out what the real topic is at a given point in the audio. If I say "camcorder" in the middle of a conversation, is it relevant to throw up an ad for a camcorder? Probably yes if the conversation is actually about camcorders. But what if I'm talking about something completely different and the word or phrase "camcorder" is an incidental side comment of no relevance to the topic at hand?
Look at this posting, for example. What's the most relevant word? It's in the title, but nowhere else. You know what I'm talking about because I mentioned it at the very beginning but after that I refer to "it" or various vaguely-relevant synonyms.
