In case consumers were worried that their smartphones, iPods, iPads and the like were going to be retro props in the next year: this past Saturday Brit Gail Davis downloaded Apple's 10 billionth app (and won $10,000 to spend in iTunes, to boot).

For the ultra-circumspect, here's another hint that apps aren't just a fly-by-night invention: According to Read Write Web's Sarah Perez, users downloaded 7 billion --70 percent--of Apple's apps last year. "Even more incredible," adds Perez, "is the fact that this mobile app growth trend is showing no signs of stopping." Quoting research from mobile analyst Horace Dediu, Perez says this means about 30 million apps are downloaded every day.

Just how big is this micro economy that World Mobile Applications Market pegs as reaching $25 billion by 2015?

There are app stores for game consoles, desktop computers, and for enterprise software. There are even app stores within apps, such as the one that popped up for apps, like oneforty, the unofficial Twitter app store, or the app store for Foursquare, hosted right on the company website. There are app stores for TVs, for cars and for printers. Simply put, apps are everywhere.

In fact, says Perez, "what's needed now are more services that help to filter, recommend, rate, review and surface those apps. No person on their own can sift through an ecosystem where hundreds of thousands of apps reside in order to find the best ones" she says.