Just how DO all those tickets end up on stubhub?

Found this just now at BoxOfficeHero: Who’s Selling out their Fans?.

They name names as to which artists have used presales and promotions to move massive quantities of tickets away from the on-sale and into presales which in some cases take up the lions-share of tickets.

Makes for an interesting read and explains what I already suspected - regular people don't stand much of a chance.