Hi Jeff / Tim
Forbidden Technologies PLC did the pioneering work in this area and were the first to deliver a working cloud platform back in 2004 with and a commercial release in 2007.
Forbidden’s platform FORscene has met with good reviews, or to put it another way you will be hard pressed to find a negative one.
All you need is a web browser with Java installed, a broadband connection of course 🙂
Recently they announced versions for Android tablets (like the Galaxy) and cellular devices such as the Nokia N900.
You can obtain guest accounts I believe and make up your own mind. Their website (https://www.forbidden.co.uk) provides a good flavour of what the platform offers and who is currently using it, the news archive is also particularly useful.
As to other platforms, there are a few Flash-based systems which whilst being easy to use do not offer frame accuracy (e.g. Jaycut).
Another system QTube is available from Quantel, obviously targeted at industry but I cannot offer comment as I’m not familiar with it.
If anyone has more details on systems such as these it would be useful to know.
Regards,
Mark.