Wearable technology and social networking is just getting started. The other day we told you about Ping, the hoodie designed to keep your Facebook profile updated. Today we have the Tweet Sleeve.

It was designed by Vanessa Sorenson and visually displays the moods of your twitter stream on your sweatshirt. The Tweet Sleeve tracks your mood and emotions by scanning your tweets, lighting up LEDs on the sleeve display.

Scientists at the Rensselaer Polytechnic Institute have been focusing on programmable tattoos for some reason and they’ve really taken the concept to whole new levels. The idea is to use hair-sized nanotubes embedded in the skin that would display an image of your choice. The image stays even after you turn off the power. I’m not sure if you can turn it off at need.

The Rensselaer eggheads see this as a social communication tool. If you are pissed off, it might display something appropriate, like a storm, which lets people know to stay away. On the other hand, if you are feeling great, it could display something appropriate for that as well. And what about all of you who write reminders on your palm? If the nanotubes are embedded in your hand, they could replace that ink and be more reliable. Seems pretty promising.