Profession and academia

This is your chance to get an inside look at the big challenges Yahoo! research scientists are working on while driving your research forward. Learn more about the real-world problems facing our industry, then focus on and solve these fundamental challenges alongside the top minds in the field.

Yahoo! Labs is inviting PhD students working in each of their core research areas to review these challenges and submit an application between January 20th - March 9th, 2012 to be considered for the Key Scientific Challenges Program.

Description and how to apply: http://labs.yahoo.com/ksc

(I am currently affiliated to Yahoo! Labs)

The Anti-Social Web: Credibility and Quality Issues on the Web and Social Media (WebQuality 2012) is a workshop to be held at the 21st International World Wide Web Conference (WWW 2012) in Lyon, France.

The workshop will provide the research communities working on web quality, web spam, abuse, credibility, and reputation topics with a survey of current
problems and potential solutions:

Assessing the credibility of content and people on the web and social media

• Measuring quality of web content
• Uncovering distorted and biased content
• Modeling author identity, trust, and reputation
• Role of groups and communities
• Multimedia content credibility

Fighting spam, abuse, and plagiarism on the Web and social media

• Reducing web spam
• Reducing abuses of electronic messaging systems
• Detecting abuses in internet advertising
• Uncovering plagiarism and multiple-identity issues
• Promoting cooperative behavior in social networks
• Security issues with online communication

Want to monitor an earthquake, track political activity or predict the ups and downs of the stock market? Researchers have found a bonanza of real-time data in the torrential flow of Twitter feeds.

When the magnitude 8.8 Chilean earthquake hit last year, researchers found that on Twitter the truth often won out over misinformation. "When a rumor is true, it spreads faster," said computer analyst Barbara Poblete at the University of Chile in Santiago.

Ms. Poblete and her colleagues analyzed how survivors of the earthquake used the messaging service in lieu of more conventional communications that had been knocked out. They discovered that in the crisis, Twitter crowds reflexively sorted facts from falsehoods, exercising a collective wisdom on the fly. She found enough measurable differences in language, citations and posting patterns to devise a way to assess the credibility of Twitter texts automatically, with an accuracy of about 70%.

"The network itself can provide a filter for valid information," Ms. Poblete said.

Full article: Decoding Our Twitter Chatter by Robert Lee Hotz at WSJ, 2011-10-01.

Image: Ars Technica.

Decision-making procedures in online social networks should reflect participants' political influence within the network.

Direct-democracy voting in large online communities may not be the best choice. The degree of commitment of different participants in online communities and collaboration systems varies greatly. In a community in which there are a few core members with long-term commitments to the project, and many other members joining and leaving the project rapidly, egalitarian democracy is neither expected nor appropriate. Thus, the decision-making mechanism is often meritocratic.

In this work, we propose a middle-ground between direct democracy (citizens vote on every issue) and representative democracy (citizens elect representatives that decide on their behalf on every issue). Our proposal, a type of delegative democracy, allows them to express their opinion directly or to delegate their power on a proxy.

Proxy delegation can be transitive: a proxy can delegate in another proxy. However, as our vote travels farther away through a delegation chain, we would like to introduce some reluctance in the way the power is transferred to other people we may not know directly. In that sense, we include a dampening factor (like PageRank does) to reduce the amount of power delegated through long chains. Technically, our system of viscous democracy is a system of transitive proxy voting with exponential damping.

Details appear in the virtual extension of the June 2011 issue of Communications of ACM: Viscous Democracy for Social Networks, by Paolo Boldi, Francesco Bonchi, Carlos Castillo and Sebastiano Vigna.

Here is the presentation I gave on this paper:

C. Castillo, M. Mendoza, B. Poblete: "Information Credibility on Twitter". Proc. of WWW 2011, Hyderabad, India. ACM Press.