There's a second blog post published at basically the same time by the CEO of Restlet with more info about the connection between Groovy and their API platform and language development: http://restlet.com/blog/2015/03/02/head-of-groovy-project-jo...
Almost 1 million of those downloads were made from a proxy server in China from Bintray during May 2014, see http://groovy.codeplex.com/wikipage?title=Blog07#2