>Doesn’t FB realize that is far easier for a user to opt-out of a feed by unliking a brand/person/page that has done a poor job of communication than it is to mess with all the account settings or for them to try to tweak their algorithm all the time to try to guess what people want?

Cuban's doubts of the efficacy of edgerank (or perhaps his doubts stemming from not knowing the purpose of edgerank) comes from him not really knowing facebook from the perspective of a consumer/user and only knowing it primarily as a broadcast tool (I've seen his posts - he's only there to broadcast). But before, I defend edgerank/facebook on this, it should be acknowledged that this guy and many like him (broadcaster for their brands) are the ones that pay the bills - and it will be interesting to see who Facebook begins to cater more to over the next few years... because advertisers' and users' interests, despite what facebook wants us to believe, will likely always be at odds with each other.