There are many other multi-paradigm languages around... even ones that combine the OO and functional paradigm: OCaml and Mozart/Oz spring to mind.<p>I think the recent popularity of Scala and Clojure, vs other languages that mix the OO and functional paradigms, really come from one thing and one thing only:  Scala and Clojure run on the JVM.  Everything else is really secondary.<p>Well, there's that and some kind of successful marketing effort going on.  Unfortunately, it's not easy to study exactly why "buzz" builds up around certain languages.  Clearly Java and C# had whole corporations' marketing departments behind them, so that probably didn't hurt.  Ruby and Python made "Perl sucks so you should program in us instead" in to a successful mantra (you know what they say about repeating a lie often enough..).<p>Clojure and Scala don't really have the same things going for them, but they are buzzword compliant, mixing OO, functional programming, and the JVM together.  Programmers hear that and it sounds sexy, so they jump on board.<p>Now the question becomes more of whether that initial buzz can be converted in to long-term success for the language, which depends less on language features than on the language's community and on further marketing (which, of course, may depend on having "killer apps" and what companies, projects, and personalities they can get on board).