http://static.tumblr.com/7drgjla/386nnw4n9/yahoo_inc._2014_a...
"We generate revenue principally from search and display advertising on Yahoo Properties and Affiliate sites, with the majority of our revenue coming from advertising on Yahoo Properties. Our margins on revenue from advertising on Yahoo Properties are higher than our margins on revenue from advertising on Affiliate sites as we pay TAC to our Affiliates. Additionally, we generate revenue from other sources including listings-based services, facilitating commercial transactions, royalties, and consumer and business fee-based services."