> Perhaps also the difference between MXM and CC0 is that the
> awareness of the problems caused by a license not including a patent
> clause is increasing all the time, and CC0 was submitted 2-3 years
> after MXM.
No, because it was with MXM, the earlier license, that you saw
heightened concern (granted, on OSI's license-review mailing list [or
license-discuss if it was pre-license-review]) about a limited patent
license grant, while with CC0, the later license-like thing, there was
initially no concern about the reservation-of-patent-rights clause.