After testing out google+ hangouts and doing a 2 hour screen share there with CannibalSmith I want to recommend using the hangouts instead of tinychat.

Sharing your screen can be more beneficial than turning your camera on for many reasons - other people can easily see when you are procrastinating (if you are doing work on your computer) and they can scold you immediately. On the other hand when you have your camera on, nobody knows if you are working or just facebooking. relevant post

Sharing your screen however has some obvious disadvantages and it can be more privacy-invading then having your camera on but hey, if you are revealing something personal on your screen then you are probably not working. There are also some cases where screen sharing can be ineffective (for example when your task at hand is to read a book or to do anything not on your computer) but places such as hangouts allow you to easily switch between your camera and screen and provide a ton of other features that can be somewhat useful. In addition to that you can write apps for hangouts which can also be utilized at some point.

As for my ~2 hour screen share with CannibalSmith - it went great, I didn't take a single break in that time nor checked facebook, gmail, skype etc. and I am one of those people that check everything 10+ times an hour.

P.S. I am writing this during a group pomodoro on tinychat because I was too lazy to do it otherwise.

Edit: Of course if there are other applications which we can use that have the option of sharing your screen then that'll probably work well, too.