[noblethrasher]

REST doesn't care about the size of the set of verbs, only that the set be constant. HTTP as one particular implementation of REST just happens to have nine verbs.

I tried to implement an IMAP server a few years ago, but otherwise I don't know much about it. However, I do recall that Mark Crispin admitted that he wasn't a very good API designer, and that much of the complexity of IMAP was due to it being intertwined with the complexity of MIME. But, I can't find the sources for those claims at the moment.