The context of those tweets is the following:
On Friday, several advertising agencies revealed the details of a proposed settlement with Facebook that would end a class action alleging the social media giant overstated the average time its users spent watching video.
According to a brief in support of the settlement, Facebook would pay $40 million to resolve claims. Much of that would go to those who purchased ad time in videos, though $12 million — or 30 percent of the settlement fund — is earmarked for plaintiffs' attorneys.
The suit accused Facebook of acknowledging miscalculations in metrics upon press reports, but still not taking responsibility for the breadth of the problem. "The average viewership metrics were not inflated by only 60%-80%; they were inflated by some 150 to 900%," stated an amended complaint.
Source: Hollywoodreporter
TL:DR: Comedysites like Collegehumor and Funny or Die made most of their money trough their own websites where they themselves could dictate who advertises and also collect 100% of the ad revenue. Youtube was only a tool to bring people to their website.
However, once they started advertising on Facebook, their numbers over there exploded, which lead them to pay less attention to YouTube and more to Facebook. What they didn't knew was that Facebook massively inflated those numbers compared to the actual number of people watching.
And since you can't monetize on Facebook but instead have to pay for getting more fans, traffic on their website fell off a cliff and with it ad rates, video budgets and I would guess overall revenue/profit as well.
So if you are one of the people asking why Collegehumor became bad, you now know who played a major role in this.