StockTwits allows you to track streams of information about stocks using Twitter. The beauty is that the stocks are like hashtags and everyone can follow along anonymously or part of it.
StockTwits streams consist of ideas, links, charts and other important financial data, summarized within 140 character messages. Users, which include analysts, media and investors of all types, as well as the public companies themselves, contribute to the stream. Investors, and others interested in stocks and markets, can easily follow individual stocks, specific contributors, as well as view the StockTwits stream across dozens of financial sites that integrate the stream including Yahoo! Finance, CNNMoney, Reuters, TheStreet.com, Bing.com and The Globe and Mail.
You can sign up directly or via Twitter and other social networks. Conversations are organized around the ticker tag and symbols. They also have mobile clients available.