It's also weird IMHO when you see an advert or movie trailer, and they tell you to visit their facebook page, rather than their own website...
Walled gardens for the less technical savvy have been the norm. Outside of the hacker/coder/geek culture, has it ever really been different? Prodigy -> AOL -> MySpace -> Facebook
It's only a matter of time when something else will replace Facebook as "the Internet". These things work in cycles.