Some professors, librarians, and administrators have begun using Twitter, a service that can blast very short notes (up to 140 characters) to select users' cell phones or computer screens. The practice is often called microblogging because people use it to send out pithy updates about their daily lives. No need to wait until you are back at your computer to let friends know that you loved the latest Paul Thomas Anderson film or that you thought of a new idea for an academic article while waiting in line at the grocery store. Twitter lets you send a text message from your cellphone to a set list of contacts, called followers, who can set the system to receive messages via their cellphones, their instant-message software, or a Web-based program. One professor uses his iPhone to post a message to Twitter after every class session as "a way to jot down a little reflection about the class ." Blackboard plans to add a Twitter-like messaging tool to its course-management system, which is used at hundreds of colleges around the country. Professors could send a message to their entire class to let them know that class has been canceled this week. Some college officials are using Twitter to keep in touch with colleagues at other universities. Twitter can be a much faster way to get help from colleagues than sending an e-mail message to a list or posting a question on a blog.