Microsoft just demonstrated a heretofore unknown capability in Windows 8 on stage at its developer-focused BUILD conference today: built-in support for NFC communication. That's significant considering that NFC looks poised to explode on the smartphone side right now, and you can imagine scenarios where you might want to quickly transfer bite-sized pieces of data between your phone and your PC -- in fact, Microsoft specifically called it "tap to share," though it's unclear whether that'll be the go-to-market name.

Connectivity with phones wasn't demonstrated on stage; instead, an NFC-enabled card was held against a prototype tablet with AT&T WWAN capability and NFC support, which transferred information (the URL to BUILD's website in this case). It sounds like you'll also be able to tap PCs together, though we'd wager that phone-to-PC is the sweet spot -- it's probably not too often that you're going to be bumping a tablet to another tablet.