Two key trends influence this point:
- Web apps are moving from server-heavy to browser-heavy. There is no getting around it. In order to create modern web apps with the features user's want, much of the code must move from the server to the browser.
- Mobile phones.
So, for any new programming language: it may have the most elegant syntax in the world, but if it doesn't run in a browser (or translate into something that runs in the browser) and/or doesn't run on a mobile device then i don't want it.
Only 2 languages (that I know of) run on the server (window/linux/unix), the browser and mobile devices:
- Java. Runs on browser via GWT. Runs on phone via Android. And, of course, runs on the server.