--- Andrew Newton <andy(_at_)hxr(_dot_)us> wrote:
Let's say Yahoo has 40 million email accounts (that's probably pretty
or low. Neilson Netratings indicates there are about 60M unique Ymail
users in the US alone (and they only measure web mail users, not POP
users -- and I'd guess their methodology doesn't include the spammers).
However, there are very few providers at an order of magnitude more
than your estimate -- there are a few more in the same.
I don't think it changes your point (just the example org), however,
I'd be surprised if there are organizations that add or subtract 100s
of thousands or millions of A records on a more than daily basis.