Twitterers Worldwide Gather for Twestival

Mrs. Rose announced plans for a simultaneous, multicity event in late January, and said that in a week she had organizers willing to coordinate meetings in more than 100 cities.

Since then, Twestival has taken off: The London event is expecting upwards of 800 guests, and Ms. Rose estimated there were a dozen satellite events being hosted around Britain. Scott Harrison, founder of charity: water, who is also helping organize the New York event, expects attendance numbers nearing 1,200. In addition, Twestival events have sprung up around the globe from Cape Town to Beijing, Peru, Tokyo and Bangladesh.