Back in February 2010 we asked Why can't you share photos on Foursquare? We discussed that this could be seen as an oversight or an opportunity for others. However, this question has now been deprecated by Foursquare with the introduction of its add photo API method, which suggests that the previous absence of a method was simply because it wasn't a priority, it was an oversight or the opportunity hasn't been taken up by developers as Foursquare had hoped. In addition to the new add photo method, Foursquare have also introduced API methods which allow comments to be added and deleted from checkins. These methods have already been rolled into the official iPhone and Android apps along with a few 3rd party apps that use the Foursquare API.
Google Maps API has become so entrenched in developer minds, that if you are looking for a mapping feature in your application, you did not look beyond them. But ever since Google announced its pricing last year, websites that have a large number of visitors have been disappointed with the potential fees that they will have to shell out for the services. These websites have responded in typical fashion and they are looking for alternate solutions. This definitely means good news to developers since having competitive choices is a positive thing.