To attract internet users to an educational website on colorectal cancer, the US Centers for Disease Control and Prevention (CDC) posted advertisements on Yahoo!, an internet search engine used by 232 million people worldwide. The six week campaign included 12 advertisements in four formats (“east module,” “north banner,” “large rectangular,” and “streaming video large rectangular”—see bmj.com ...

We use Yahoo! Toolbar data to gain insights into why people use Q&A sites. For this purpose we look at tens of thousands of questions asked on both Yahoo! Answers and on Wiki Answers. We analyze both the pre-question behavior of users as well as their general online behavior. Using an existing approach (Harper et al.), we classify questions into “informational” vs. “conversational”. Finally, fo...

We consider the online version of the well known Principal Component Analysis (PCA) problem. In standard PCA, the input to the problem is a set of vectors X = [x1, . . . , xn] in Rd×n and a target dimension k < d; the output is a set of vectors Y = [y1, . . . , yn] in Rk×n that minimize minΦ ‖X − ΦY ‖F where Φ is restricted to be an isometry. The global minimum of this quantity, OPTk, is obtain...

This paper answered a question – why people want to share knowledge in virtual community setting. Without sharing volition, mass collaboration, often happened on the Internet, becomes non-existential. Mass collaboration has been a significant base for the success of Wikipedia, open source software, Yahoo! Answers, etc. With a model modified from Rational Action Theory (TRA) and data collected i...

Community question answering (CQA) systems such as Yahoo! Answers allow registered-users to ask and answer questions in various question categories. However, a significant percentage of asked questions in Yahoo! Answers are unanswered. In this paper, we propose to reduce this percentage by reusing answers to past resolved questions from the site. Specifically, we propose to satisfy unanswered q...

We describe the system that won Track 1 of the Yahoo! Learning to Rank Challenge.

Internet auctions on eBay and Yahoo allow sellers to list their auctions with a “buy-now” option. In such auctions the seller sets a buy price at which a bidder may purchase the item immediately and end the auction. In the eBay version of a buy-now auction, the buy-now option disappears as soon as a bid is placed, while in the Yahoo version of the auction the buy-now option remains in effect th...