"According to Official Final Results announced by Google China at 7:40pm Dec 24, 2008:
The Chinese phrase "Liu Yifei" is the No. 1 Vertical Search phrase for images in China for the year of 2008.
(By comparison, the more general phrase "wallpaper" is ranked 6th)
Also the Chinese phrase "Liu Yifei" is the No. 2 Mobile Local Search phrase in China for the year of 2008.
(Beating out search for "Free Games" at No. 4 :P - No. 1 is the phrase "QQ" - the most popular messenger program in the world [*1])
For the category of Most Popular Search for Actresses in China of the year 2008, "Liu Yifei" is rank No. 4
Note: The results above are applicable for Google China only and is final as of searches up to Dec 21, 2008
Source: Official Google China Results at:
http://www.google.cn/rebang/2008/chuizhi.htm (Vertical and Mobile Local Search)
http://www.google.cn/rebang/2008/yule.htm (Entertainment Search)
Wan Mei's Notes:
 Windows Live (MSN) is reported to have 294 million active users worldwide but QQ has 317.9 million active users (almost all in China) (Source: Wikipedia)"
Thanks Wan Mei for your insight on the numbers! Just to share another link which shows Yifei's popularity in sg.yahoo.com:
"A not-so-little spat between bloggers Dawn Yang and Xiaxue topped off a year of strong interest in hot celebrity women such as all three Beach.Ball.Babes, Megan Fox, and Liu Yi Fei."