If you look at AB very early in the morning you often find lots of "answers" that are in fact spam. There can be a couple of dozen of them, all done by the same person.
People do these updates overnight as they think they will stay on the forum longer before being deleted (they are also often done by people in the USA during their "day").
When the AB editors logon in the morning and see this spam they then trawl round the site deleting it.
Which is why you see so many deleted answers.