> I'll give it a shot:

[snip excellent info]

In addition to what Markus has written, you can also read the (somewhat
brief) explanation at: 
http://phrogz.net/ProgrammingRuby/language.html#symbols.


IIUC, symbols are implemented internally as immutable strings. Take a
look at String#intern or String#to_sym (
http://www.ruby-doc.org/core/classes/String.html#M001310).