Saturday, June 12, 2010


I went underground for past two weeks, preparing for my tutorial on ad exchanges at EC. I will put the slides online as soon as I write up some of the new results, but meanwhile the older papers are here. There were like 70+ people in the audience Monday morning. In the first half, I described my AdX model. It is a block diagram with a sequence of 7 operations, and immediately I knew the audience just wanted to get past it and see theorems/results. But diagrams like that hide the nuances of the many decisions one makes in building a system and I took some time to point out to the audience some of these decisions. Then the audience got lively and started poking at the design and after a prolonged back-and-forth, I felt comfortable that the audience had an appreciation for the model and the underlying system. The second half was mainly research results, some old, some new. Tuomas Sandholm, David Parkes and others during after the tutorial had many questions.

In the afternoon on Monday, Aranyak and Vahab spoke about ad allocation problems. These are variants of bipartite matching problems from online to budgeted, stochastic or whatever. Aranyak spoke about online Adwords problem and discussed throttling and quality scores which are difficult areas to theorize, but with deliberate speak, Aranyak managed it. (Puzzle: algorithms to maximize avg value of items in the knapsack.) In a conflict of styles, Vahab who went next, took bigger bites and larger chunks of problems, more focused on social network and display ads problems.

Tuesday was the workshop on sponsored search auctions. Michael Ostrovsky spoke about setting reserve prices in Yahoo!. The discussion for or against reserve prices has swung around a few times, and Michael's work showed, via live experiments at Yahoo! that revenue can be optimized by tweaking reserve prices. He claimed 9-digit $s improvement and there was a lot of debate about this among the audience later. Preston McAfee spoke about Yahoo! as a large publisher network that had to decide how to split its ad impression among various sold contracts as well as when to go to an ad exchange for the spot market. This was the talk I was looking forward to most since it was closest to my interest, and Preston has a good sense of humor ("it is bad when the audience not only looks at the watch, but starts shaking it in disbelief"). Preston basically chose to talk about his paper on representative allocations; many questions still linger in audiences' mind about whether this is a suitable allocation, is it really appropriate to price them by spot market outcome and others (that came up during my tutorial when I discussed this paper), but Preston said Yahoo! uses these ideas.

Tim is always a pleasure to listen: he spoke about all auctions that have VCG equilibriums for sponsored search. John Hegeman gave one of the most interesting talks in the workshop on ad auctions at facebook, including their choice of VCG (not GSP). Susan Athey gave an insightful talk on detailed modeling and understanding sponsored search including price elasticity.

Some important discussions:
  • Moshe Tennenholtz, who has been on all sides of the aisle from academia to startups and corporate labs, is a real thinker. Among other things we discussed: how much research/academia does Apple, the company of innovation as most would boast, support?
  • Chris Dellarocas who has done some very interesting work with reputation mechanisms, asked what parts of sponsored search research could (should) Academia contribute, and is not in the realm of only corporate research.
EC + STOC + CCC + Wkshps: collision of many overlapping communities. I could not sample all of the fare.



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