Jason Calacanis is talking about it after Allen Stern brought up the issue.
While I agree with their various ideas, I see the ad model being similar to what Facebook has done with their newsfeed advertisements — but more importantly, where users after making a purchase on Amazon.com could opt-in to share that purchase via Twitter [and even earn 4% of any purchases from that]. I mean Twitter begs the question, “What are you doing?”. I just purchased something I’m really excited to get!
Somehow the user’s Amazon.com account would be tied to their Twitter account, and post the purchase to Twitter (“Steve just bought the book ‘The Richest Man in Babylon’”) — then people that click the link and buy that item, and the user ["Steve"] is compensated with 4% of the sale (for promoting the sale of the book to their friends; and Twitter makes 1-2% as well from Amazon.com).
Or Twitter just works a deal with Amazon.com [and others], where on the purchase receipt page, it asks if the user has a Twitter account — if yes, they input their username [or full login credentials] and the item is posted to their Twitter account. If no account, Amazon.com is promoting the Twitter service to their millions of users, which adds millions of more accounts to Twitter.
The question is, how are etailers working with Facebook now, to have a purchase added to their newsfeed in Facebook? Maybe the etailer adds a line of code that contains the newsfeed info and is shot over to Facebook, where the user logs in to confirm?