The Maps app allowed for navigation on the PS Vita, much like a GPS or cell phone. Along with the Maps app, several functions in the Near Social Suite will no longer function when the next updates rolls out in March. Sony has yet to specify which of those features will be removed at this time.
The YouTube app is no longer available to download as of today, January 28th. It will no longer be supported as of April 20th.
Sony has not yet commented as to why these features are being removed from the Vita, but it’s possible that, given that most Vitas are Wi-Fi only, the Maps app is probably not terribly useful for most customers. As for the YouTube app, it’s a mystery, though there are still plenty of ways to access the site on the system.