I think he was talking of a scenario where the option to disable it did not exist, in which case I completely agree with him. But if there was an option to turn it off, I think we can all agree that most users would choose to and facebook would probably be saved.

Facebook relies on the user having a positive experience with the site. It aims to smooth social interactions. God knows how many girls I've "stalked" (I dislike this term but that's a different point entirely) and I've used the information I gained from anonymously browsing their profile to chat them up. Call me a creep but us primates like using tools :)

Believe me, most people stalk others. I firmly believe Facebook is where it is today thanks to the privacy that enables us to do so.

The dutch social network Hyves introduced this a few years ago, and set it on by default. They got a LOT of comments over this (which they handled quite well: sending around flowers and all). But within a day it reverted to off by default. You can still switch it on, so others see your visit's, but I think it's not that common. Power users (paying) do get some aggregate stats tho (last month, 40 people, of which 54% girls, visited your profile.)