Sony are planning to extend the PlayStation Network to hardware other than the PS3, while at the same time "evolving the PS3 into a platform for web services." The PSN currently offers games and media content to PS3 owners, but future deployments could see it available on Sony Bravia HDTVs and mobile devices like the PSP and Sony Ericsson handsets.
"Sony has begun the transition from a closed system to an open one ... Next we will be expanding the PlayStation Network to hardware other than the PS3, because the number of PS3 units sold puts a limit on the scale of the network possible. Sony has a vertical structure for each product line, an organisational structure that resists change, so it will take time to achieve this network growth. However, a large number of employees share my opinion on this" Howard Stringer, CEO, Sony
Sony has been tipped as planning to jettison the UMD drive currently used on the PSP for pure online delivery in future iterations. While the company has denied such a policy, this latest statement does suggest that UMD will take a step back from the primary source of title distribution.
Given that Sony have made headway in standardizing the XMB GUI across much of its consumer electronics products, it seems likely that the PSN will evolve into a catch-all digital distribution system. As Stringer says, the physical number of PS3 consoles sold will be the hard limit to users of the Network in its current format.