For example, if you want to share a picture: first enable Bluetooth and NFC (called "Tap & send") in settings. Go to the picture hub, select a picture (by viewing) and hit the three dots and choose "send...". Now you'll have a selection of possible ways to send this picture to someone. "Tap and send" sould be the first option in the list.
I can confirm it doesn't work with Android devices (just test with my Lumia 925 and Nexus S).
yea tap+send is what you're looking for. if you want to send files to an android device, you must go the old-school way, that is pairing your phones through bluetooth first, and then send the file afterwards.
it works in IE if you're trying to send a link to Android.
other than that I think it doesn't work for much else.
I really hope that there'll be a solution to make it work with Android because..well they have 80% smartphone market share.