Bad design doesn't make sites successful. It's more that sites that for some reason have a strong grip on the user can get away with being lame in other respects. But you can't learn anything from this lameness, because it's random.
I think the post is mostly tongue-in-cheek, he isn't actually suggesting you do these things, just pointing out that there may be more important things to worry about.
No. It's true, it also happens in craiglist, ugly = success, it may be because is less scary without design to the masses?
Woah, woah. Craigslist may be ugly, but it's a UI masterpiece. The ugliness of MySpace comes at the expense of the UI, which makes it infinitely more shitty.