The Windows 8 app store has passed the 20 000 app mark, of which 18 000 are free. No one’s quite sure when it happened but WinAppUpdate, which keeps track of this kind of thing, reckons it was probably some time on Tuesday.
Today’s totals: 20,610 apps worldwide in the Windows Store (broke 20,000 on Tuesday, I believe). 17,958 of those are free (87%).
— Win App Update (@WinAppUpdate) November 22, 2012 
As The Next Web notes  however, not all of those apps are available in all markets. Canada has more apps, at 13 882, than the US (12 675) for instance.
Despite that caveat, it still means there’s been some pretty spectacular growth. Just a couple of weeks ago , the number of apps was hovering around the 14 000 mark.
That’s an impressive addition of 453 apps a day, and much closer to the nearly 500 it was getting just after its launch. That growth rate isn’t likely to slow down any time soon either, especially as developers look to ride the wave of people buying Windows 8 devices over the holiday season.
In the end though, the store won’t be a success if the apps it’s selling aren’t of a decent quality. Google and Apple’s app stores both have their fair share of godawful apps, but they still manage to attract products from top developers (largely because of the massive prospective audience they offer). Microsoft has the potential to offer something similar with Windows 8, as long as the devices running it don’t sell as slowly as the Surface has so far.
Microsoft’s Windows Phone Store meanwhile has 120 000 apps  — still way behind the Android and iOS offerings.