Basically, users sign up on "the site", uploads data onto it, and generates a javascript tag which will fetch the data he/she uploaded on "the site".

The user will then put the

    <script type="text/javascript src="https://thesite.com/user/23423/share.js">
        theSite.insertTo('#dataView');
    </script>

    <div id="dataView"></div>

I have no idea if there are services like this. Does google Docs have anything like this?