In many parts of Asia, namely Japan and Korea, though sometimes in China as well, people think your blood type affects your personality and character. Certain blood types are thought to be more reckless and less responsible. http://en.wikipedia.org/wiki/Blood_types_in_Japanese_culture These kind of prejudices can influence an employer's decision much as looks (based on photo), gender, age, etc can.

这里的一些日本公司很喜欢问面试者的血型，觉得血型能带表一个人的性格，这一点可以做为判断面试者合不合适这份工作的一个小依据吧。

They don't want the blood type, at least in China mainland I think.

It was on the news from one of the TV stations in Nanjing. A city with population over hundred thousands, but only few hundreds people are blood type "O". Some of these people may have moved outside of the city, only hundred people remain in the city. For emergency concerned, these people has been proposed to keep tracking. Logically, it appears that the resumes and profiles show the applicants blood type is to attract the employers' preference. On the other hand, the employers may be either in compliance of the law or being influenced by others.

Really？I think the type of blood is useless for employer...