This original post by Jason Fried was making fun of Twitter which went from 1bn to 25bn. More background here: http://www.forbes.com/2009/10/15/venture-capital-software-te...
Another post from DHH said that the value of FB was not 33bn & it's now roughly 120BN http://37signals.com/svn/posts/2585-facebook-is-not-worth-33...
Not saying 25BN & 120BN are the "right" valuations but most people would agree that the prices that 37s made fun of seems like great deals. They could still go back to less than 1bn & 33bn (users leave, consumer trends change, get bored etc) but those are different risks not monetization risks that 37s is making fun off.