Google has added a new security feature to warn GMail users when there are suspicious log-ins to their e-mail accounts. The feature, now being rolled into Firefox and Internet Explorer, will flag GMail log-in from multiple locations and flash the following warning to an affected user. It also provides a quick glance at the user s current IP address to help match up against possible suspicious logins. It will also provide more details on logins in an account activity window.
Source: https://threatpost.com/google-issue-gmail-suspicious-activity-warnings-032410/73736/