It’s not quite 4OD, it’s 4OD catch-up, but as far as I’m aware the only difference is the inability to watch archived shows, such as old episodes of Green Wing or Black Books… but maybe in time this will become a reality too.
So what has prompted this new service? I’d like to think demand from mac and Linux users, but who knows. The shift from Microsoft’s WMP to Adobe’s flash player has certainly made the whole thing more accessible though. Whilst it would be nice to have a completely FOSS solution, this is unrealistic at present and I think Channel 4 should be applauded for taking steps to make life easier for non-windows users.