I dislike when companies "hate" on other companies and copy what they do. Amazon does well in the Kindle marketplace; Apple feels they need to dip into that. Google does the same thing, and this is no different. Why does FB feel the need to get involved in this business? They have enough to get right with their current model. Destroying another business is just downright mean and spiteful.

It's not that companies are hating on each other. Quite the opposite. They like Foursquare so much that they might think about acquiring it, or "replicate" it. As a company, in a capitalistic system, you try to grow as much as you can by leveraging your assets, which, in Facebook's case, are their users. Not to mention, FB as a social network might not exist if a new, better social network pops up in the near future. What then? While they are growing, it's a great strategy to try to get into other businesses so even if one fails, you have a fallback plan. Moreover, the more connected we are through Facebook and the network that we have created on it, the higher the likelihood that we'll have a hard time leaving Facebook.