No subject

a programmer, not a user.

Sure, the "or any later version" is not a problem for the user (if
the new one is less restrictive, all the best; if it is more restrictive,
he/she can use V2 -- until new programs are "V3 or later").

For a programmer, the clause "or any later version" may be a problem:
if the new license is less restrictive, then I (as a programmer) am
giving away more rights than I planned to. But the "or any later version"
clause is optional (though suggested); so people really concerned about
the issue can use GPL2-only.

There are sound reasons for using the "or any later version" clause, as
it allows closing possible problems with V2 without breaking compatibility
with future packages (that will be V3-or-later, probably).  While I
understand the concerns about giving away unplanned rights, I'm reassured
by the FSF ensuring that new versions will be similar to versin 2:

      9. The Free Software Foundation may publish revised and/or new versions
    of the General Public License from time to time.  Such new versions will
    be similar in spirit to the present version, but may differ in detail to
    address new problems or concerns.

[this is from the GPL itself; still you (as an author) are not bound to
 use the "or any later version" clause]

I don't know exactly how this qualifies on legal terms, but it looks
pretty clean to me: first authors and users agree on a license, and
the author accepts later changes to the contract made by a trusted
third party (the user may or not accept, it's not a problem since
"at your option" applies).  This is legal even in Europe. Yes, I asked.

But the "trusted third party" can't force unexpected effects on the author,
since the author explicitly agrees to point 9 above: if the FSF goes
mad and issues a non-copyleft or even non-free license, the "any later
version" can't be enforced because of point 9. No, this I didn't ask
to lawyers. Any confirmation or denial is welcome.

/alessandro