I think he means that you are signed up on the fan page's mailing list. Companies of which you are a fan gain access to your social inbox, which I would assume allows them to garner much more of your attention than if they reached for your spam-filtered, labels-and-filter-ridden, adblocker-protected email inbox.

Another intangible but real benefit is the backchannel that fan pages open from the users to the company, and the other fans. Hard to quantify indeed.

What I am curious to see is hard data on acquisition cost of fans vs. mailing list subscribers, and subsequent mailing conversion rates.

People who are up to three degrees of separation can still have an influence on us. If you have a friend of a friend of a friend who has been influenced by advertising, the influence can trickle through his friends to you, and you don't even realize you were effected by advertising. The influence of advertising is pervasive and unavoidable.

Everyone says they aren't influenced by advertising.

The fun part of that conversation comes when you point out that they're wearing Nikes.