Not as big a deal as it sounds, to be honest.
The native PSN storefront on PSP is closing down, Sony has announced.
After March 15, users in SCEA regions will no longer be able to purchase or download content by accessing the PlayStation Store on their PSPs. In-app purchases will still be available on PSP even after the store closes.
This change doesn't mean your handheld will be useless, thankfully - all your past purchases will be available to download from the Download list, and you'll still be able to buy PSP content through the SEN web store, as well as a limited selection via the Vita's PSN Store app.
No word on if and when the European storefront will be affected.
This news is important for Vita owners, too, since the Vita's backwards-compatibility with digital PSP titles is quite a draw - especially for fans of classic games and JRPGS. It's also interesting in the context of the axing of the PlayStation TV.
— PlayStation (@PlayStation) February 29, 2016