Danah says supporting the Mac is required for social computing.
You can build enterprise software that doesn’t work on a Mac but you CANNOT build social technologies that don’t work on the Mac. Who are key driving forces behind sociable technology? Freaks, (independent) geeks, academics and other marginalized populations. What do marginalized groups use when it comes to technology? Surprise – they use subversive tools. Conferences organized by geeks, freaks and academics are like walking into an Apple distribution warehouse. If you only lived in this world, you would think that Apple makes up 70% of the market share.
I’d go further and say that any social networking infrastructure MUST be inherently cross-platform, but I’m sure that lots of people are/will try to prove that wrong. Lets hope for their continued unsuccess.