Webapp Show Document holds instant document, whiteboard and browser-sharing sessions with anyone. You can collaborate on documents in real-time without the hassle of installing an application, and everyone involved can save the results.
This net meeting platform offers support for Microsoft Office and Open Office files as well as image and text files, which you can either upload or open from a url. With each session you have an hour to work with up to 50 simultaneous viewers (don't worry, there's a notification five minutes before the clock runs out to give you time to save the document) and it only takes a click to turn a viewer into a presenter.
Best of all, you can open multiple tabs within each sessions, so if you suddenly require a face-to-face meeting, just open a Google Map tab and show everyone where to go for free pizza. Note: The shared browser function is still in an open alpha.