On June 21, Facebook CEO Mark Zuckerberg confirmed rumors that the site would be launching location-based features sometime in the future. Continuing rumors are swirling that Facebook’s location-based features may be a ploy to pull users of sites like Foursquare, Brightkite, and Gowalla back into the Facebook world.{Mashable}

Dubbed “check-in” sites, Foursquare, Brightkite, and Gowalla were all created with the idea of people being able to learn about the resources in their community from other people in the community. Users “check-in” when they arrive at a destination and can offer comments about the location. Users can also browse locations close to them to find a new restaurant, bar, or other attraction.

But all of these location-based network sites may not be the best thing for users. Facebook users have been robbed after posting their plans in status updates. {CNN} Meanwhile, Twitter users have been hit in a similar manner. {Social Reflections} Apparently, disclosing your location in a Tweet or status update is like hanging a banner over your front door that says, “We’re not home. Please take all of our stuff!!” Quite frankly, it seems that stalkers will have an easier time stalking with location updates.

Looking back to the unrest in Iran after their disputed elections, many protesters used Twitter to organize and communicate. Following the protests, which often turned violent, groups of hackers claiming to be an “Iranian cyber army” hacked Twitter, Baidu and a number of other large sites, which could have potentially sensitive data about anti-government activists. With the planned location based updates, spying on users could now be as simple as following or friending them – no advanced technical skills required. While the threat to most Americans may not be in the form of a cyber army or violent militia, it’s only a matter of time before a more serious crime results from location updates.

We’re not ones to wear tin-foil hats, but it’s certainly worth remembering that when it comes to announcing your plans and location, not everyone who follows is a friend.

At left, Brightkite Starbucks badges, at right, a Starbucks Mayor Offer on Foursquare

For those who don’t know Foursquare, it is a social network based around your location.  Using the Foursquare app on your smartphone of choice (native apps available for iPhone, BlackBerry, Android and Palm WebOS phones) you “check-in” to locations, and can see other people who have visited and what they say about it.  By checking in more than anyone else, you become the mayor of a location.

Mayors have typically been given special advantages, being able to cut in line, a free drink or two, and other discounts to name a few.  Now, Starbucks is offering discounts to any mayor of a specific Starbucks.  The deal is $1 and “NEW however-you-want-it Frappuccino blanded beverage.”  The deal is good until June 28.  It may not seem like much, but Starbucks isn’t exactly known for frequent discounts.

If your allegiance is with Starbucks and not a particular network, Foursquare competitor Brightkite was actually first to partner with the coffee mega-chain on Frappucino focused badges, though initially there were no special discounts. {TechCrunch} If one Frappucino isn’t enough, check in with both services though, and in the future you could find yourself with double discounts. Brightkite wouldn’t get into specifics, but hinted that there was more to come beyond the profile decoration. {Brightkite blog}

It seems that Starbucks is really going all in with location/mobile focused social networks.  It will probably be a few months before results of the programs are announced, but it serves as great publicity for both Starbucks and the networks.  As the networks start battling it out to be the mobile check-in app of choice there’s bound to be some overlap, but it will be interesting to see how they differentiate themselves going forward.

Foursquare screenshot via {Mashable}