Just when you thought Google Latitude would no longer haunt your dreams, the service has been updated to make it a smidge creepier than before. Now Latitude tracks your location history and alerts you when your friends are nearby -- two add-ons that could make stalking that much easier!

Location History is the creepiest of all, so thankfully this service is only for personal use and is not shared with Latitude friends. The way it works is Google pinpoints your trail of breadcrumbs and determines where you were by where you paused. (Click on the above image from Google's demo to see a larger screen showing how it works) From there, you can check your history and piece together last night's manic bender, or, you know, a harmless cross-country trip. And if the ghost of your whereabouts proves to be more than you can handle, you can delete selected history or the entirety of it at any time. Despite sending shivers down my spine, Location History could have some practical uses. And while it's currently private, the rise in popularity of location-based services such as Loopt, Stalqer and FourSquare may convince Google to later selectively publicize Location History to friends.

The other add-on to Latitude is Location Alerts. Sick of checking Latitude every time you want to be sure your spouse is really headed to the grocer

y store? Location Alerts is designed to remove that burden by notifying you via e-mail or text if one of your friends (or enemies) is nearby. Combined with the omnipresent powers of Location History, Alerts establishes frequently-visited locations, so you won't get messages when someone is in an expected place like at home or in the office. Google says it might take a week or so to learn your behaviors, but believe: it will definitely learn your behaviors.

Always concerned about privacy, Google made these features opt-in, so you don't have to worry about your ex peering at you through the window of that coffee shop. Not yet, anyway.