The protocol that allows us to use the internet as a telephone has to be my favorite thing online. It was a hard choice (I am a very big fan of World of Warcraft), but after realizing the many different ways in which I make use of it, and expect to continue doing so, I realize it is my favorite thing. VOIP is an amazing tool that helps us keep in touch with family and friends at a much more reasonable cost. But aside from all the obvious reasons for liking it, I also believe it has the potential to change the way business is transacted and regulated online on a global scale.
Examples:
* A program for Mac called "iChat" gives users the possibility of "chatting" by either voice (as in a telephone call) or by video conference. 3-way voice or video conference is also possible and loads of fun!
* A small black cordless phone that I have at home connects directly to my modem and allows me to call anywhere in the world for a very low flat fee.
* Finally and maybe even more importantly, World of Warcraft is in the process of incorporating their own VOIP "chat" to the game. This will be an amazing addition to the game because now we wont have to use caps lock to indicate our discontent, but we can actually yell at the mage who just killed the rest of the party. ^_~