From ranking blogs to predicting posture

Making news in the blogosphere
The study, named the best student paper after being presented by graduate student Jure Leskovec at last year’s International Conference on Knowledge Discovery and Data Mining, subsequently set off several rounds of editorializing on sites that were either included and excluded from the lists, effectively generating some news cascades of its own.

“I haven’t yet written a paper about my own paper,” Guestrin said, laughing at the irony.

Among the many comments either praising or second-guessing the study, blogger Bora Zivkovic questioned the usefulness of ranking blogs based on 2006 data (“eons ago in Internet time”) and pointed out that his own highly-ranked blog, Science & Politics, had been mostly unattended since June 2006.

But Guestrin said the academic exercise, by design, only looked at one year’s worth of entries. And blogs such as Zivkovic’s, which excelled at posting big stories earlier than other sites but included relatively few items overall, would score higher based on the algorithm’s consideration of inlinks, outlinks and posting frequency than a blog that picked up big stories but interspersed them among many more items.

Another outcome of the study, Guestrin said, is a glimpse into what specific networks of bloggers consider newsworthy, a group decision-making process that helped propel sites devoted to coffee lovers and parents who homeschool their children into the top 100 blogs.

“It all depends on what the Web vernacular of the time is,” he said, speculating that a list based on 2008 postings would likely be more heavily skewed toward political sites.

Less obvious applications
Beyond its usefulness for news aggregator sites and others seeking to tame the Internet’s vast jungle of information, the research has led to less obvious applications.

In one offshoot, Guestrin’s group is collaborating with researchers at the UCLA-based Center for Embedded Networked Sensing to optimize how algal blooms are monitored. For surveying efforts at California’s Lake Fulmor and Lake Merced, among other bodies of water, Guestrin’s team has contributed a Cascades-based algorithm that points to the best route for a sensor-equipped boat to maximize its recording activity, given its dependence on limited battery power.

Guestrin is also working with another group at Carnegie Mellon to help design a chair that can detect subtle differences in the positions of people sitting on it, a tool geared toward senior citizens and disabled patients.

The starting point, Guestrin said, was a sensor that covered every square centimeter of the chair, but cost a cool $10,000. The challenge was to smartly position a much smaller number of sensors that could still accurately capture information identifying whether the sitter was reading, sleeping or hunched over to one side. Guestrin’s prototype sensor is now down to about $80. Eventually, he hopes, it will be used as benchmark for predicting posture.

Jon Kleinberg, a professor of computer science at Cornell University in Ithaca, N.Y., who has worked with some of the project’s collaborators previously but wasn’t involved with the Cascades effort, said the algorithm has provided “a powerful unifying framework for thinking about things ranging from news and diseases to fads.”

With a limited advertising budget, for example, a marketing firm would need to strike a balance between maximizing visibility while minimizing its overall investment. If the budget allowed for just a few billboards, hanging one in Manhattan’s Time Square would undoubtedly capture plenty of eyeballs.

“But you’d likely not want to place a second too close, or you’d simply be reaching the same crowd with both,” Kleinberg said.

As for identifying the online network that would collectively capture the biggest news early on, he said, the new research has helped to map out the landscape of sources with influence in the blogosphere, at least with like-minded readers.

If a blog is particularly close to a breaking story, though, is it good at noticing the news or adept at amplifying items into news?

That question and the larger issue of how online sites not only propagate but also shape information as it travels, Kleinberg said, are fertile grounds for further research — and undoubtedly, for more blogging.

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