Our mail server has somehow erroneously been blacklisted and so we have added about 100 emails of that "Spam" to that half a trillion. I'm sure we're not alone.

The blacklists aren't infallible and get messed up and tend to be very slow to respond to errors or worse just don't bother (or even worse demand money to be removed in one noteable case).

What the article should say is that AOL blocked half a trillion emails, god knows how many of them were legit emails or how many really were spam...