I don't think you can really estimate the popularity of any programming language by looking at forum activity, especially not if you're only looking at JavaRanch.
I've noticed that there is a lot of interest in Scala, I was at JavaOne in San Francisco last year and there was a lot about Scala, and Artima's
Programming in Scala book was in the top 10 of the JavaOne book store. You can find a Scala forum
here and on
StackOverflow there are also a lot of Scala questions.
I'm involved in a Dutch Scala user group myself, it's fun, every month we have a meeting where someone holds a presentation and after that we do some small programming practices together.