It's already there
Internal (non-banner) advertising has been in Facebook for ages. Two examples are Apple Students and Red Bull U; Apple Students was a bit tiresome with random messages to members' inboxes; sometimes weekly, sometimes monthly. Red Bull U is far more occasional, generally only doing the adverts for their far and wide zany days like the flugtag. Both were clearly associated with the companies, not just mockups by fans.
It's a status thing; like wearing a branded tshirt, though here you're not paying for giving sponsorship. When it gets invasive, it gets tiresome. Regular emails selling the same or near-similar things are a pain; behind-the-scenes ads that make sure that the banner ads that appear while browsing the site are relevant to your interests are good, because it's better than random banner ads that try to sell you things you're not even remotely interested in.
Those who Fear the (info)Reaper will just leave their Interests blank, or whichever other fields the information is harvested from. It's easy to freeload by providing minimal information, or unverifiable information. It's easy to adblock. Changing the mechanism so it's displayed as a userbox-type thing is utterly ignorable, since it'll most likely be swamped under the poo flinging and aquaria and werewolf statistics. News feed settings can be changed to ignore these things.
While I don't agree with some of the changes Facebook make, I'm also not paranoid that they're stealing my information and using it for dastardly purposes, because I just don't provide that information. Perhaps they'll flag me as a poor user in some later silver-gold-platinum-diamond feature doodad, but for now it simply has no effect.