Wikipedia showed a blackout page today to protest, and it will last for 24 hours.

In my paper with Feng Zhu (You can download the paper from here.) published in June 2011 in the American Economic Review (AER), we studied the effect of blocks of the Chinese Wikipedia on incentives to contribute.

A direct effect is obviously that many people can no longer contribute to Wikipedia.

The following figure suggests that contributions from China reduced significantly after the block.

The bar chart further compares the contributions from different regions before and after the block.

An indirect effect is that people who were not directly blocked also reduced their contribution significantly. In the paper we estimate that the reduction in contribution from those who are outside China is more than 40% within the 4 weeks after the block.

The next figure shows the number of new contributors. It can be clearly seen that each block (shown in shaded areas) significantly reduced new contributors.

The lesson learned: information needs to be free. Legislation not well thought out may bring unintended consequences.

It was my birthday on June 1 (yes, the children’s day, that’s why I don’t get old).

My friend John was visiting, he was bored so dragged me to watch the Horse Race in Happy Valley.

The point is really not watching horse. We were busy checking the statistics of the horses and played a few hands. I typically don’t do gambling because I always believe it is a form of “stupidity tax”. This time, however, I played. Of course, we lost.

Just before we were ready to leave, I got the email (can’t imagine the days without iphone). It was the acceptance letter of my paper by Management Science.

So I guess this is the best birthday gift ever. I started working on that paper in 2003, then presented it in 2005. Presented it as my job market paper around the world (literally), and it won me quite a number of great job offers. However, it was such a long journey to publish it. It stayed at one particular journal for 18 months before I got two very irresponsible reviews.

Probably we were one of the first to write on the topic, when we first submitted it in 2006/2007 the reviewers could hardly understand what we were talking about. After several years of extensive study by many other colleagues, finally the value of the paper gets recognized. When we submitted it to MS in 2010, one of the reviewers said:”This is a very timely study to look at dynamic features of keyword auctions, while the majority of the literature still relies on static models.”

Some friends asked me if the reviewers knew the “inside information” of my birthday. I guess not, even if they do, it would be hard to coordinate so that the editors can send out the notification exactly on that day.

For the record, my dear reviewers, please do not wait to surprise me only on my birthdays. Surprise me now! Surprise me any time!

Then a question arises: suppose mutation can trigger some effects so that an animal suddenly becomes poisonous. Why the poisonous feature cannot stay like the colorful pattern on insects? Fortunately not, if yes, then many things we see today will be poisonous!

One explanation is that the colorful patterns are salient features, so they can immediately be effective to protect the insects. In the long run, this feature can be passed onto future generations. The poisonous feature is not salient. So a wolf will continue to eat that poisonous rabbit and there is no chance for the poor rabbit to pass on this great feature.

In a sense, these poisonous rabbits are like experience goods. Before you consume them, there is no way for you to know their quality. You only learn about their quality after you eat them, but then it is often too late for you to regret. It is a blessing for us that there is no review systems (e.g., those similar to Yahoo movies, Yelp, etc.) in nature. If yes, then the poisonous rabbits can pass on the feature and today we will have to face many more poisonous animals.