We already have to applications for WebEx; one for the general webex and one for Desktop/Application Sharing. We should have similar one for GotoMeeting for Desktop/Application sharing.
This would allow users to access gotomeeting webinars etc. but not allow desktop/application sharing, which is a breach of IT security policy of some companies, especially government departments.
Not sure if that would be possible. I did some google searching and didn't see anything that could be used to distinguish a client side screen sharing from other traffic. My guess is that once a client connection is established, all data is sent over that connection, so blocking the screen sharing would require the ability to decode the established data streem. That doesn't seem likely.
I'd recommend contatcing Goto Meeting support for some advice.