The Google News Blog announced they have joined Twitter to automatically post links to top stories on Twitter via @GoogleNews. Many news sites automatically post stories to Twitter as well, but Google News recently started to do this as well. I believe Google News also powers @News_By_Robots, but I do not have official conformation on this.
The growth of Twitter is tremendous and more and more media, as well as average users, are coming to Twitter.
Google joined Twitter in February, since then, many other official Google services joined the program. We have a big list of the search engines and their employees on Twitter that we hope to keep up to date. But most recently, I spotted that @GoogleWebspam has joined Twitter. The account is currently not active, but it has been confirmed to be secured by a member of the Google Web Spam team.