All the following share one similarity EXCEPT ______.

A．LookSmart
B．CMGI
C．Altavista
D．Microsoft

A．There are too many pages or hyperlinks on the Internet, so people usually use search engine to find a certain site.
B．More than 8 search engines are accused of selling their search engine spots by Commercial Alert.
C．The headquarters of Commercial Alert is in Portland Oregon.
D．The search engines are Web guides.