Twitter.com

Broadcast where you are and what you're doing right here and right now by texting from your mobile phone. Your pithy posts will pop up on all your friends' cell phones so they can keep abreast of everything you do, in real time. Each "tweet" must be brief—no longer than 140 characters. The service, created by Biz Stone and Jack Dorsey, exploded onto the moblogging scene earlier this year. There have been some bugs—big ones like vanishing accounts and mysterious spikes in individual networks—but none of these hiccups seemed to have dampened the public's enthusiasm. In fact, membership reportedly doubles every two to three weeks. Meanwhile, a number of third-party tools have launched to enhance it: Twitterific, Twitteroo, Tweetbar, Twitterholic, Twittervision... Kyte.tv's kyte Mobile service takes things even further, letting you broadcast your own "kyte show" in real time with photos and video shot with your (Web-connected) cell phone.