Google wants its users to know that, yes, it is reading their e-mails. But there is a reason.

The company updated its terms of service late Monday evening, describing how and why its software looks through users' content in order to serve up personalized ads, catch spam and tailor search results.

Our automated systems analyze your content (including emails) to provide you personally relevant product features, such as customized search results, tailored advertising, and spam and malware detection. This analysis occurs as the content is sent, received, and when it is stored.

The slight update comes after the company fought off a class action lawsuit from Gmail users who said the company's practices violate state and federal privacy and wiretapping laws. The lawsuit alleged that Google was illegally scanning private e-mail messages sent and received in Gmail accounts. Earlier this month, as Bloomberg reported, U.S. District Court Judge Lucy Koh rejected the class action lawsuit, saying that the class wasn't cohesive enough.

Each instance of interception, she said, would have to be considered separately.

Google has said all along that its users understand that e-mail and other content must be examined and processed to provide the services that Gmail offers -- particularly its Priority Inbox, which automatically sort the mail coming into users' inboxes.

In a statement, Google said that it changed the terms of service to make that clear to all Google users. "These changes will give people even greater clarity and are based on feedback we've received over the last few months," the company said in a statement.