A study by Forrester Research predicts an upswing for dynamic languages like PHP, Ruby, and Python. Why should one use this crap? PHP is the Visual Basic of the Web, but it's also a security nightmare. Ruby receives rave reviews because of its high-level OOP approach. I think it's just another Web2.0 hype. And Python is praised for its 'fun' factor, but I can't see any arguments beyond that but baiting against Perl.
So tell me what you can do with these languages you can't do so by using Perl or a C derivate. (Source)