The links are much appreciated. Thanks! The social network article is especially detailed , glad you pointed it out.
Funny, I was thinking of the exact same example of modeling diffusion of innovations when you edited your post to include that. Using a social network, you could simulate the diffusion of information about a product from the starting point of an advertisement. So theoretically, you could highly optimize your ad campaign to target just the right people that will spread the word of your product the farthest.