It seems that the Like Button on Facebook is going mobile and as such, this means that developers on web apps can now incorporate the custom button into their apps, making much easier for the user to get to grips with the Like Button while using apps running on their Smartphone or tablet device.
According to a posting on the Facebook Developer Blog by Andrew Rothbart;
The new Open Graph built-in like action makes it easier for people to share content from your app. While the Like button is a great way to let friends share content from the web back to Facebook, the like action enables you to build your own like buttons for your mobile or web app and drive distribution across Facebook. You can use the new like action to implement your own like button for a more integrated experience with your app on web and mobile platforms, as Instagram and foursquare have done.
Source [Inside Facebook]