Alasdair: I never actually worked at Sun, or had any involvement in OpenSolaris prior to OpenIndiana – believe it or not I only started using Solaris in 2008, which does surprise a lot of people. I run a Managed Hosting company in the UK and I saw a lot of promise in technologies such as ZFS, Zones and SMF, which allow us be a lot more agile than our much larger competitors. I got stuck in and learned everything I could. And within 6 months, most of our clients were going into Zones onto Solaris servers.
Then in 2010 when Oracle bought Sun Microsystems and the future of OpenSolaris became very uncertain, I started to worry. Nobody knew what would happen next. Oracle had canceled several open-source projects and there was complete radio silence. I had been attending the London OpenSolaris Users Group (LOSUG) quite a lot. And I decided to investigate the possibility of forking OpenSolaris, via a weekend hackathon I advertised through LOSUG. A surprisingly large number of people attended. Nobody at that point had attempted to assemble the whole distribution outside of Sun. At the end of the hackathon it became apparent that it was entirely possible, with some hard work and dedicated volunteers. So we set to work.