It might seem from the business press and even consumer momentum like everyone has a smartphone these days. But it’s not even owned by a quarter of the population. And it may seem like Apple is completely dominating the app market, but that’s not true either. In fact Nielsen’s new ‘App Playbook,’ busts open a few myths.

The first of the company’s monthly app reports surveying more than 4,200 people who had downloaded an application in the past 30 days, shows 21% of American wireless subscribers owned a smartphone at Q4 2009. That’s up from 19% in the previous quarter and significantly higher than the 14% at the end of 2008. More than 14% of mobile subscribers have downloaded an app in the last 30 days. Smartphone owners own an average of 22 apps; feature phone (no internet access): 10. Owners if iPhones own an amazing average of 37 apps; Android posts second with 22 and Blackberry actually trails Palm and Windows with ten.

Other data:

• Games are the most downloaded – both free and paid.
• Facebook, Google Maps and Weather Channel are the most popular apps across smartphones. For example on iPhones Facebook has a 58% penetration rate,  iTunes (48%), Google Maps (47%). Facebook is clearly favorite app, but MySpace is hugely popular among teens; LinkedIn attracts adults 25-44.
• News/weather: Weather Channel was used by 58%; age distribution across sites was similar, save for Time Mobile and Thomson Reuters.
• Shopping: Amazon and eBay lead (57% and 41%).
• Search/Map: skew male, particularly Instamapper (80/20).
• Video/Movie: skewed towards males; Imeem and Moviefone show a higher proportion of young users.
• Music: iTunes, Pandora, Sirius XM appeal more to males, while Yahoo Music almost evenly split (51/49).