While Ubisoft has been the poster-boy for DRM as of late, Capcom apparently introduced a variation of the technology in its release of Final Fight: Double Impact through the PlayStation Network.
Kotaku reports that the game requires a constant connection to PSN in order to play, and, if the console’s Internet connection is lost, the game exits entirely. An affected gamer on the IGN boards wrote to Capcom about the issue and received this response, purportedly from a Capcom representative:
Yes, there is DRM. This was employed to combat the rampant "PSN Sharing" that has been going on over the last year. We're sorry that your family cannot play the game on their individual accounts (same console). This is a limitation of the Sony network. We are not committed to do this with all titles moving forward but the only way to evaluate impact was to try it with one title first.
Kotaku also reports that the publisher apologized "for the issues consumers are having,” and would look into ensuring that notice of the game’s DRM is included in the description of the title posted on the PlayStation Store (which currently contains no reference to DRM).