This seems to be completely out of the blue, so take it lightly if you will. SamFirmware, the guys that continuously publish leaked ROMs and whatnot have tweeted that Samsung will be looking at leaving Windows Phone and will cease innovating for the platform from 2013 onwards. It seems odd due to the success of Samsung handsets on Microsoft's OS, but let us take a look at the larger picture here.
Could Samsung be focusing on Android? Not sure, they already have solid devices like the Galaxy S II so it could be that they have decided to take bada seriously, especially since with Android they are experiencing legal issues and have to pay Microsoft royalty.
Google will now play a role in hardware as well as software with Android, while Microsoft holds continuous tea parties with Nokia. But they're still two completely different relationships. Manufacturers were sceptical about the Motorola acquisition whereas Acer and others are still pretty excited about the future of WP.
Should this be true, 2013 is still two years away. If the platform really does capture the market by storm with Mango then perhaps Samsung may change their tune. Android (and Google) need Samsung, but it could be that bada will be competing for market as well as WP.
However we look at it this way, Samsung does seem to have a relatively healthy position by supporting both WP and Android, which makes it seem odd that they would choose to pull out from either one of them.