If you are one of the seven or so lucky people who owns a Google Nexus S, has been invited to participate in the Google+ beta, and happens to have an active NFC tag about his person, you'll be able to replicate a video posted to YouTube recently.
The short clip shows the aforementioned smartphone running the Google+ Android app and reading data from a near field communications (NFC) tag.
Also known as digital wallet, NFC is a short range wi-fi signal which a range of companies are planning to use for card-free payments, as well as bombarding you with marketing messages whenever you walk past a suitably-equipped digital billboard or console.
The hidden function, which Google probably didn't want you to know about just yet, is limited to reading data but asks users if they want to share it with other Android Apps.
You can watch the video here.