This reminds me of Blinkendroid https://code.google.com/p/blinkendroid/ which was the first time I'd seen multiple devices interact with each other like this. Sadly that project never managed to get much traction despite how much potential it had.

Can't actually think of a case where I would want or need this. Even my Chrome tabs followed me around is kind of annoying lately, since I lookup different things different places without much interest in them elsewhere. E.g. I'm not going to read HN on my phone.

I think this is fantastic, but I couldn't find API docs / tutorial anywhere on your site. Demonstrating use cases is important, but I don't think it's enough to get developers to download / register.

Reminds me (in a way) of Chrome Racer. (http://www.chrome.com/racer). Could this be using WebRTC for the fast device-device communication?

It reminds me a lot of this awesome, open source, swiping library developed at the MIT Media Lab: https://github.com/Swyp/swyp

I couldn't get this to work between a S5 & Nexus5. What are the requirements? Same wifi? NFC or Bluetooth enabled? How does it know what sides the devices are on?

I can't see the use case for wanting to send some information between devices this way. Perhaps PONG or other types of video games?

Love this. Opens up a lot of very native interactions. Eg. snipping a document to the larger tablet.