Shatner - 7:29 pm on Nov 12, 2011 (gmt 0)
One of the ways the BigBrandX's are pulling this off is by not only republishing the same story over and over again, but by republishing the same story on multiple domains.
For instance they might publish a story on BigBrandX.com and then when they need to push it to the top again, republish exactly the same story on BigBrandX.uk.co and so on. It's the same exact content, just repurposed over and over again.
It's exactly the kind of thing smaller sites get penalized for, but BigBrands are immune so they use that immunity to manipulate the system.