Social networking is now built for two.

These days it's easy to meet someone on Facebook or Twitter, but once you're in a relationship it's in danger of being lost in that online noise.

The answer comes in the form of new apps that are basically social networks just for you and your partner.  

You can share messages, status updates, and pictures only with that special someone. One of them, called Twyxt, turns red when you're both using it at the same time.

It lets you "freeze" your partner's screen if you're having an argument. And when you make up, there's a "spank" feature.