I am not very clear what are the differences, as both seem to be very similar?

I use a cam with maybe upto 2 people, if its more I connect to the TV for simultaneous group chat!(voice&visual at the same time)!

If you are using Video conferencing, which software do you use and why?

What were your user experiences so far? (i.e. cost, compatibility with laptop/netbook/TV, security, user-friendliness, reliability, how long does it take to get started...)