When webcams first became a mainstream computer accessory, internet was slow, and instant messaging did not support them. Now, almost every instant messenger supports the use of a webcam, and there are ever increasing numbers of people with broadband internet access.
The other day, I was helping someone with their computer, and they had mentioned that they might set up a webcam so they can talk to family oversees. I think this is a great tool to use in such cases. I have even used my webcam when talking to my mom, who lives on the other side of the state.
Another important factor is the price. Web cams have floated around the $40 dollar range for a number of years. Today, you can find sales on web cams for as cheap as $10-$15 dollars. Some of those even include a built in microphone!