Google certainly is focused on where you are and letting others in on that information. A week after unveiling Google Latitude, which enables people to track the exact location of friends or family through their mobile devices, the company has announced that its Gmail software can now show the location of e-mail writers.

"Some time ago I noticed how all mail systems tell you when an e-mail was written, but not where it was sent from," said Marco Bonechi, a Google software engineer, in a blog post. "Because I love to travel, the first question in many messages I receive is "where are you?" and by the time I answer, I am often somewhere else. So in my 20% time, I wrote an experimental Gmail Labs feature that detects your location and appends the city region and country names to your signature."

Bonechi noted that people can use the new Location in Signature feature by going to the Labs tab in Gmail under Settings and then clicking on Signature Preferences.

"It'll use your public IP address to determine your location, so it may not always be that accurate," he noted. "For example, if you're at Heathrow airport, IP detection may put you in Germany. If you want more accurate location detection, make sure your browser has a version of [Google] Gears that supports the location module. That way, Gears can make use of wi-fi access point signals to recognize that you're actually in London."

Bonechi also added that users who want to keep their location private can disable the option or delete their location from specific e-mails.

Google's tracking technology hasn't received full support from security experts.

Just a day after Google Latitude was released, Privacy International called Google's new mapping application an "unnecessary danger" to users' security and privacy.

Simon Davies, director of the London-based privacy rights group, said in a statement that Google Latitude could be a "gift" to stalkers, prying employers and jealous partners.

But Google was quick to respond. Replying to questions in an e-mail, a spokeswoman said their engineers and designers took privacy and security concerns into account when they created Google Latitude.