Attribution modeling for online marketing
Interesting multichanel attribution work by UPENN: Analyzing the Customer Journey:Attribution Modeling for OnlineMarketing Exposures in a Multi- Channel Setting
In a nutshell, they build a Markov chain that models the user exposure to different marketing channels and model who the different components help for convergence.
The second problem many retailers are facing is to try and filter out botnet behavior vs. real users behavior. One interesting paper in this domain is which uses graphs is: BotGraph: Large Scale Spamming Botnet Detection. The second paper is An analysis of social network based sybil deferences.