Short quote from Google’s Privacy Policy:

When you send email or other communications to Google, we may retain those communications in order to process your inquiries, respond to your requests and improve our services. When you send and receive SMS messages to or from one of our services that provides SMS functionality, we may collect and maintain information associated with those messages, such as the phone number, the wireless carrier associated with the phone number, the content of the message, and the date and time of the transaction. We may use your email address to communicate with you about our services.

So dear Android phone users, be careful what you text from your device. Pretty soon Google will know all your secret recipes, love romances and future projects. But hey, it’s only for your benefit:

We have a good faith belief that access, use, preservation or disclosure of such information is reasonably necessary to (a) satisfy any applicable law, regulation, legal process or enforceable governmental request, (b) enforce applicable Terms of Service, including investigation of potential violations thereof, (c) detect, prevent, or otherwise address fraud, security or technical issues, or (d) protect against harm to the rights, property or safety of Google, its users or the public as required or permitted by law.