In a move that surprises no one, Facebook is taking on Foursquare with last night's launch of Facebook Places.

Facebook isn't a public company. Neither is Foursquare. Why should you as an investor care about the leading social network's plan to offer a location-based check-in service?

Well, let's make this relevant to Joe Investor.

  • Microsoft's (Nasdaq: MSFT) Bing is generating the maps that Facebook is using in allowing users to post their whereabouts to their profile page.
  • Apple (Nasdaq: AAPL) is the first device to get the app, though some phones can access the feature with certain browsers if they support geo-location.
  • Yahoo! (Nasdaq: YHOO) was rumored to be bidding on Foursquare earlier this year. If so, it may have skirted disaster by not completing the purchase. Facebook exceeded the 500 million-member mark last month, and it should have no problem ramming this feature down its userbase's throat.

Does this now hit close enough to your portfolio?

If not, we can approach this from the public companies that may be negatively affected if Facebook Places takes off.

To get there, we need to take a closer look at the sudden popularity of check-in apps bearing silly names along the lines of Loopt, Gowalla, and Foursquare. There's a certain self-absorbed mind-set that comes with wanting to tell your virtual friends the restaurant you're eating at or the boutique you just walked into. I hear you, but chest-thumping narcissism is the trait that fuels popular Web 2.0 darlings Twitter, Facebook, and Tumblr blogs.

It's also very viral. Maybe it starts off with your most pretentious friend lifting pinkies at a trendy trattoria for all to know, but before long it becomes the roadmap to social getaways at the neighborhood watering hole with buds you actually want to hang with. Are there security and privacy concerns? Of course -- though the paranoia appears to be, for the most part, overblown.

So let's get back to your stocks. Do you own OpenTable (Nasdaq: OPEN) or Citysearch parent IAC (Nasdaq: IACI)? These are the kind of websites that can take a hit if Facebook becomes the hub of social outings.

How about Google (Nasdaq: GOOG)? If folks are following trusted friends around -- on Bing maps no less -- they may not need to hit up the mother of all search engines the next time they're looking for a new sushi place to check out.

So let's go back to the opening sentence here:

In a move that surprises no one, Facebook is taking on Foursquare with last night's launch of Facebook Places.

There's suddenly a lot of investing gravitas in that action -- isn't there?

Should Facebook go public? Share your thoughts in the comment box below?

Google and Microsoft are Motley Fool Inside Value recommendations. Google and OpenTable are Motley Fool Rule Breakers choices. Apple is a Motley Fool Stock Advisor recommendation. Motley Fool Options has recommended a diagonal call position on Microsoft. The Fool owns shares of Google. Try any of our Foolish newsletter services, free for 30 days.

Longtime Fool contributor Rick Munarriz was checking out Facebook Places last night, but ketp being told that the feature isn't available in his region. He does not own shares in any of the companies in this story. He is also a member of the Rule Breakers analytical team, seeking out the next great growth stock early in its defiance. The Fool has a disclosure policy.