Media Guardian complains today that Channel 4’s new on demand service only works on Windows XP and Internet Explorer. Vista support will be added in the next few weeks. One of the reasons cited for the service not being available on Macs is that Apple’s FairPlay system isn’t available for license to third parties.

Users also need to download special software to view programmes.

Five’s (a.k.a. Channel 5) fee based on demand service requires Windows and Internet Explorer. This too requires you to download special software to view programmes.

Sky Anytime PC is a similar service for Sky customers. This uses the same underlying software as Channel 4’s on demand – Kontiki, but it’s unclear whether users need to download other software in order to use Sky’s service, or if they can re-use Channel 4’s software.

The pattern here is clear. We have a number of companies providing their own solutions to delivering and showing content to viewers. This puts a monumental stall in the usability of the services and potentially hinders the growth of on demand content.

So guess what will happen when movies and TV shows come to iTunes in the UK?