Google today introduced "Account Activity", a feature that will track account holders' monthly usage of Google services. Each month, Google will send you a password-protected report that will statistics on your email usage, search history, and latitude check ins and plot the data against your usage during the previous month. The service incorporates your usage across all devices, including Android products, and allows you to see where, when, and on which device your account was accessed.
Right now the report works with your Gmail, web, and latitude usage, though Google says it will add more of its services in the coming months, which presumably leaves room for tracking Android-specific stats. You can opt in through "Account Settings" in your Google account, and opt out at any time. For more information, visit Google's official blog at the source link.
Source: Google Blog
