No, not at all. I meant in terms of hype and popularity. Otherwise, it seems quite solid to me, and they (Groovy and Grails) are in active development.
Gosu is the language developed by Guidewire, a major insurance software provider :) (I work in the insurance sector. I wish my company bought Guidewire).
There is another interesting jvm language: http://gosu-lang.org/compare.html
Web framework for gosu: http://ronin-web.org/
But it is even less popular and I'm not sure if it even has an active community.