A great service that records your listening habits and musical preferences. Just think of the future, when small devices can produce personal algorithms for sexual, culinary, cinematic, and literary preferences, not to mention clothing, where you like to walk or ride your bike, et cetera. Combine that with the inevitable Google Earth built into everyone's wee wetware PDAs implanted in your brain, so you can find the perfect date, or a complicated one once the perfect ones get boring. It can predict your level of, say, cycling skill and suggest routes for you as a culmination of different routes used by others in the past depending on how much challenge or exercise or scenery you want.
I love the future.