unite and IPC

Is there any way to communicate with an application running on the users desktop? I have an application that generates data and want to communicate with that application from a unite app. I've had a look through the javascript doc. and as far as I can see there's only a file i/o. which would be a bit limited.
if that's not possible, is it possible to launch a program and capture the output from javascript?
just for the sake of an example I have a program that captures the user's screen, but I on;y want to capture the screen when someone is making the request. being able to tell it when to make the capture would be useful. I don't want to write the capture to disk either if I can help it.

thanks
Peter

Can your application make http requests? Couldn't it just AJAX results to your Unite service?

It doesn't but it could. but that's probably just a big an overhead as using the filesystem.