Until now Tags has allowed users to tap their phone on NFC tags at various venues to read information off of them (unfortunately these aren’t very commonplace yet — I have yet to actually use the feature in a real-world situation). But this update also adds write support — you can now create your own tag on the phone, and specify what information you want to share, be it your contact information, a link to a website, or a snippet of text. Then, when someone else with an NFC-equipped device taps your phone with theirs, they’ll be able to immediately receive this information (much in the same way you would using Bump). And, if you happen to own any of those NFC stickers that Google likes to show off, you can use the phone to write data to those, too.
At this point the feature is going to be more of a novelty than anything, but it’s likely that the next iPhone will support NFC, and it won’t be long before we start using it for payments and third-party applications take advantage of it, too.