[atq2119]

> Strictly speaking, the only license that doesn't have the copyright holder retaining any rights is the lack of one (i.e. releasing to public domain).

This is a bit nit-picking, but releasing without a license is pretty much the opposite of releasing to the public domain.

If you release without anything, the raw unmodified copyright laws apply, which are rather strict and give the recipient basically no rights - certainly no right to redistribution.

You have to make some kind of explicit statement if you want to release something into the public domain. That's why things like CC0 exist.