The Beatles -- You Could Argue They're Well Known

I was reading some things about the Beatles' albums coming out on 09-09-09 and whether they'll be on iTunes or not.

One comment struck me as sublime, from a guy named Bob:

The Beatles are arguably one of the best selling musical groups of all time, so having their catalog available on the store of the largest seller of downloadable music is the kind of synergy that makes business people say “ca-ching!”

Yes, I suppose you could argue that The Beatles were one of the best selling musical groups of all time. If you could find someone to argue with. Because it's an objective fact beyond dispute. "The Pope is arguably a well-known Catholic."