Baidu SEM now has a database of over 300,000 websites for Baidu union ads. And they are categorized into 25 fields and 115 sub-brands. Baidu union ad users can select the websites they want to put their ads on according to the categories. For example, if a cosmetics company wants to promote themselves via Baidu union ads, targeting on young fashion female, they could choose the category of “lady fashion”, and then the ad will be put on all the websites under this category.
Besides, users can also select the website they want to show their ads individually..
The real disadvantage of Baidu union is the Malicious Click and unlike Google, Baidu will not return the loss from malicious click to union advertising users.
Source: ebaidu, CNNIC