The picture is a bit confusing
Yahoo! is now HortonWorks. Their stated goal is to not have their own derivative release but to sell commercial support for the official Apache release.
So those selling commercial support are:
- EMC (reselling MapRTech, but had announced their own GreenPlum (free and commercial))
- IBM BigInsights (free and commercial)
+ Amazon, indirectly, that do their own derivative work of some release of Hadoop (which version is it based on?)
Photo of Steve taken from LinkedIn