[charliepinglass]

Not the guy you're asking, but thought I'd answer. This may not be referring to true "immunity", but Matt Cutts did say this around the time Panda was first released:

"And we actually came up with a classifier to say, okay, IRS or Wikipedia or New York Times is over on this side, and the low-quality sites are over on this side."

http://www.wired.com/business/2011/03/the-panda-that-hates-f...

So there is something that is specifically recorded for well-known sites that likely prevents them from receiving the same treatment as other, smaller sites. And anyone who works in SEO can tell you that not since Vince has it been just about links.

[codeka]

He's referring to a classifier that can tell the "quality" of a site, not the size of the brand.

[OGinparadise]

Google cannot "read" content so in essence it's the size of the brand that matters, unless they suppress it manually via search quality raters.

Brands escape major updates, something we saw especially after Panda. As soon as some major sites were hit, they changed the algorithm. Google does not algorithmically punish certain sites for link buying and other shenanigans. I suspect that after a site reaches a certain level of score (not calling it PR) it's golden. So buying 123456789 comment spam links for "Matt Cutts" on fiver will not do much, but 500 links to mymomscookies.tld will cause them to go to page 10, or dead in the water.

Google doesn't seem to care because small sites don't give them pr problems (Audi and Macys would) and small sites will be forced to advertise, if they want any traffic. Notice the perverse inventive? Cut the free traffic and increase adwords' business.