I just read a post where someone on here stated he expected facebook to become a mini-www on their own...with no (or little) need for many people to leave their website (well..basically what google is doing, now, just without ever sending visitors away).
I had read about the facebook becoming a separate kind of www before, already, and must say it made sense (im not saying itll kill the www :-), and of course its more like part of the www, but i hope yo uget the point).
However, what happens if facebook grows and grows and grows and becomes that huge? How will people find content *within* facebook?
I'd say they'll be using search.....and if it becomes huge (everyone being able to set up their own facebook pages, etc. already)...then they'll need a ranking algorithm just like google has one, wont they?
In other words I dont see facebook necessarily as a SEO-killer, but some sort of separate www, that'll need a sophisticated search engine as well.