What does PocketStation do?

News just appeared that Sony might be reviving PocketStation soon, but what did it actually do?

Wikipedia lists few compatible games, of which about half are Japanese versions. It was only originally sold in Japan, so no wonder many of us missed this device. The page isn't very clear on what it does.

Solution 1:

The pocketstation is simply a special Playstation One memory card with a screen and a few buttons. A few select Playstation titles could send special data to the Pocketstation where you could play a game on the Pocketstation itself, independent of the Playstation, and sometimes send data back to the game for in-game rewards. A notable user of this system was Final Fantasy 8, whose North American version included this feature, despite the US never getting the Pocketstation. Those of us (me) who imported a Pocketstation could use it on NA FF8 on NA Playstations, however.

If you're familiar with the Dreamcast's VMU "Visual Memory Unit", it is exactly that, though it loaded in the memory card slot, not the controller, and was not used as a display in-game.

Also noteworthy is the Playstation 3 actually recognizes and can read Pocketstation data (it will even display a Pocketstation icon), though it cannot send data back to the Pocketstation, making it somewhat useless unless you need to read it as a memory card.