There is an oft-cited story going around that the many worlds interpretation implies the existence of 10 worlds, and this number apparently comes from Everett, III himself. It is often used to argue that the many-worlds interpretation is just not credible. However, the truth is that the existence of infinitely many worlds, (or practically speaking infinitely many of them, maybe, if space and time would turn out to be discrete and finite), is a basic requirement of quantum mechanics itself, regardless of interpretation. Everett, III cannot be blamed for that, just for coming up with the ludicrous number of 10 to describe infinity.