All my new projects will be released under MIT / those I work on will be switched, which will still means the same as before: Do wtf you want with this code, no need for any naming/license copying.
After reading some articles I realized that public domain does not always work since some countries do not allow it and its also unclear what happens when the code causes problems <-> lawsuit.
Ill also try to add a s.license = ‘MIT’ to all gemspecs, to make license management easier.
Michael Grosser, the Blog 
How about just using the Creative Common’s public domain dedication (CC0, http://creativecommons.org/publicdomain/zero/1.0/ )? It does the same thing (in a legally sound way) and also includes a disclaimer of liability.
Sounds good, but its way more complicated then MIT and also less known, so e.g. if I would encounter a project on CC0 I would not know if I could copy it / use it without reading (and understanding) the whole legal stuff.