Yahoo OpenHackNYC: The Cake

Last weekend Yahoo came to New York for an Open Hack Day, and it was great!

I was invited to speak on a panel on semantic metadata, moderated by Paul Ford ( along with Marco Neumann (KONA) and Paul Tarjan (Yahoo/Search Monkey). The panel was a lively discussion, and we got some great questions from the audience.

After the panel, I stayed around to participate in the hack competition. Yahoo! provided a fantastic space, with free-flowing coffee, snacks, comfy chairs and plenty of Yahoo folks and other hackers around to give advice and play foosball with. I teamed up with Diana Eng, Alicia Gibb, and Bill Ward to create the Cake!

The cake is attached to a laptop via USB. A program running on the laptop accepts a delicious tag and retrieves a list of recent popular sites for that tag from the delicious API. Finally, it iterates through each URL, downloads the page, and computes the sentiment of that page relative to the tag — basically, is the content of the page positive, neutral or negative?

The signal is output to an ardiuno (hidden in the middle of the cake) which turns on the appropriate set of LEDs. There are four sets of LEDs on the cake, one in each quadrant of the delicious logo, one each for positive sentiment, neutral or inconclusive sentiment, and negative sentiment, and, of course, one to let us know that the cake is turned on.

I wrote the sentiment classifiers between around 3am and 6am Saturday morning, so they really were a hack! I trained them on movie reviews data, working with the assumption that 5-star reviews contain positive terms and 1-star reviews contain negative terms. I wouldn’t recommend this approach for a serious attempt at sentiment analysis, but it worked well enough.

We won the food/hardware hack prize, shared with the awesome MakerBot team!

We had a great time creating and presenting the hack. Thanks, Yahoo, and most of all, thanks to Alicia, Bill, and Diana for a really fantastic, silly weekend.

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