I feel that the inability to share ones own purchased digital media either discourages purchasing or encourages downloading of possibly dubious versions. Most people who have bought DVDs or CDs move them from room to room, perhaps to the car, taken them on holiday even, in a caravan or a motorhome. That is legitimate use of the license bought. I personally have totally avoided buying films from iTunes because I am unhappy with being tied in. Other members of my family either were ignorant (the common general scenario - and you can only explain so much before "I just want to watch a film on my..." comes up) or rely on me as a "get out of jail" option. I think that this is starting to blow up in the media (if you haven't heard about it try searching news sites regarding Bruce Willis and his iTunes account).

But it is not just the movies (or films as I say it) and music scenario alone. Families want shared photo albums, document storage and a shared calendar. They also don't want to rely on an IT professional in the family to consider temporary and permanent access, security, resilience of data (i.e. backups but also who can delete what), protection from supplier failure (what if the company holding your photos goes bankrupt) and ownership (no I don't want to be the poster boy for [insert serious but personal ailment for comedic effect] so I don't want to grant usage rights). Until group accounts, ownership and permissions are truly considered and easy then we are holding people back. And possibly innovation.