The collection of copyrighted content from around the web can be "outsourced" to the users of a site like FunnyJunk or (as the letter points out) YouTube. The content is then hosted and advertising run next to it, generating revenue for the hosting company.
This basically allows companies to leverage the fans of content against the creators of that content. People upload The Oatmeal comics to FunnyJunk because they like the comics! But by doing so they are enabling the redirection of financial gain from The Oatmeal to FunnyJunk.
To fix this redirection, the owner or controller of the copyright must then file DMCA requests for each individual instance of infringement at each individual website. It's an impossible task, as The Oatmeal has pointed out repeatedly. And I don't know of any way to crowdsource it--to incent The Oatmeal fans to do it for The Oatmeal.
We're all cheering for The Oatmeal now, but tell the same story with The Pirate Bay and Sony Music, or YouTube and Viacom, and would the comments below be of the same tenor? I would guess probably not. But the structural issue is exactly the same.
I'm not advocating for any particular solution, just trying to draw parallels.