Google has invented another great tool: Google News Alerts, which are e-mailed to you when news articles appear online that match the topics you specify. Email news alerts aren’t new but what makes Google’s so powerful is that Google News trolls 4,500 news sources continuously throughout the day — and you can set the alert to send you links to related articles as soon as Google News find them. So if you’re writing about the debate over the Episcopal Church’s first openly gay bishop, for example, you can set an alert to send you an e-mail as soon as any of 4,500 news sites posts an article containing the words “gay and bishop.”