Server-Side Languages. With great power comes great responsibility. [The Web Explained: Part 4]
Languages: Many options to accomplish similar outcomes. The number of programming languages that exist seems to be anywhere from 700 to 25,000 . There's no way you're going to learn them all, and in reality, there are probably about 50 that are in any sort of wide usage in the wild, so don't waste your time learning some esoteric programming language. This list is not exhaustive, but the reality is that you're likely to run into one of these open-source languages in your travels: Ruby