And here is the content of the em-mail I got today:
Can you please explain to me the reasons for such cruel act? First Laying off SSM veteran employees and cancelling a promising game on PS4 and now redducing the number of apps on PS Vita thus its versatility. I thought the PS Vita will get more apps in the future and not the opposite. I will keep the app and will never delete it.
foursquare on PS Vita
We have important information to share about foursquare on PlayStation ® Vita.
Sony Computer Entertainment Inc. will no longer load the foursquare app on PS Vita from 1 April 2014 and was removed from the PlayStation ® Store from February 12, 2014.
You can still use your foursquare account on other mobile devices or on the foursquare website, where data will be stored in your account.
We hope you continue to enjoy other social networking applications available on PS Vita."