How come? Can you explain your point a bit further?

Sure. I didn't want to put a how-to manual in this thread on the day of the attack though.

HN has a big table of closures representing actions a user can take. Loading certain pages, such as the reply link on a comment creates more of them. They time out after a while, which will get you "unknown or expired link". Intentionally creating a few million of them ought to fill up the server's memory and would be a more effective way to to impair the server's functionality than simply requesting the home page a few billion times.