, Sven Groot wrote

Dryad never managed to build up any momentum outside of MS. This is because there was a very long delay between the publication of the paper and the first public release, which was not only basically a crippled version but also had an "Academic use only" license. They just kept it out of the public eye for too long, in which time Hadoop built up a very strong following.

Yes.  When they finally started to talk about it (and I have only ever seen it mentioned on C9), it wasn't immediately available, and only then with a license that makes it irrelevant for most of it's potential customers.  It was as if they didn't really want to release it in the first place.  Or maybe they were trying to gauge reaction and make improvements before some eventual commercial license release -- which never came.  I wouldn't think many people would be willing to invest the time and effort to set up something like that if they didn't have the license (and pricing) info up front.  Nobody ever knew about it.  Another good idea that died on the table.