My experience with start-ups is that people there are usually so happy to get money and time and option to choose technologies they like. Sometimes they don't know what language or framework they like, so they choose what is considered to be today's cool instead. I'm not criticizing that, after all, Ruby is a good combination of cool and useful, but I'd say that Perl5 is more useful (to me) even though less cool. No flamewar intended.