I don't use the word "evil" pretty much for anybody, but I think the business model is at the very least screwed up. If it's a valuable service, why do they have to be so shady? I'd happily pay facebook $10/month or whatever (I can't imagine they make more than that on ads on me) to use their service. The problem is that they make it seem free, and people just don't understand the extent to which it tracks you. It's the same business model car dealerships use when they try to steer you towards negotiating in terms of monthly payments to avoid your focusing on the bottom line cost--you can get more out of people when you hide the ball about how much your service actually costs them.

Indeed, my non-technical friends have only the vaguest idea that their usage has a correlation with the ads (Facebook isn't exactly full-disclosure about how their targeted ad model works). This is especially true with kids. You think my 13 year old nephew understands the privacy implications of using Facebook?

There is also the worry of what happens when Facebook stops being "the good guys" (which is a possibility for any corporation). What happens when the constant push to meet analyst expectations causes them to monetize user data in more and more insidious ways? I don't think anyone thought at first that the credit card companies were "evil", but the whole credit card/credit score mafia is doing legitimately devestating things to many peoples' lives now. Some people can't get jobs because of their credit scores. What happens when Facebook starts selling user data to employers doing background checks? Do we just assume that Facebook is full of "people like us" so they would never do that?