for example, here's an idea that's been kicking around in my head. (i'm not the right guy to start this company, so i'll just throw out this there.)

you know how people at the gym often track their workouts -- "3 sets, 10 reps, 150 lbs" -- with pencil and paper? that's so 20th century. why not build a sensor network for exercise equipment? you get on a scale or weight/cardio machine. it knows who you are -- RFID in your membership card? -- and it wirelessly uploads your workout data from that machine to a server.

as a gym member, you get a login to an accompanying web app, which is automagically populated with your data. you can set goals, track your workouts + results with pretty graphs, etc. no more paper+pencil tracking -- just work out and log in.

sell this sensor/software platform to gyms (or perhaps the equipment manufacturers), and you've got yourself a business.

where does the internet come in? well, aside from the tracking app for individuals, with all this aggregate data, you'd revolutionize exercise science. is interval training really better than marathon cardio sessions? more weight+fewer reps, or less weight+more reps? even basic collaborative filtering would be cool: "people with bodies like yours got these results with this workout plan."

it'd disrupt the (absurdly lucrative) personal training industry.

point is, out there in the "real world," there's tons of data that's just waiting to be aggregated and analyzed. that'll certainly be the basis of many interesting companies.

This is why I think mobile has such great potential. A platform that the user carries around with her all day that has rich sensors such as camera, microphone and NFC. It's perfect! (apart from the small screen but thats a small price to pay for such access to an user)