Why is it called "punycode"? What's "puny" about it?
I emailed Punycode RFC writer Adam M. Costello, and he replied by quoting an email of his from 2002:
It is “puny” in three senses: The repertoire of characters used in the encoded strings is small, the encoded strings are short, and the implementation is small.
I have a longer write-up about it here: