I highly doubt that's the reason for Debian being successful... are you
forgetting that most GNU/Linux systems out there don't have a policy at all,
and only around 10 in total are more strict than Debian?
I don't know the history behind Debian's success, but I'm sure it's not as
simple as having proprietary software in a repo like almost everyone else
does (and not even by default, or in the main repository).
By the way, don't overgeneralize; I don't have a problem with these ads in
Firefox, and I was nothing but confused when bloggers described it as a
"betrayal". They're just filling up empty space for users that don't have a
browsing history yet. At the same time, though, I don't think it's wrong for
a derivative of Firefox to remove the ads any more than it's wrong to remove
Mozilla's Google sponsorship. It's not Trisquel's job to make Mozilla money.
