A Google post discusses the crucial problem of threats to online free expression. See: Securing online freedom.
In my opinion, as long as search engine keywords are sent in clear text, governments, ISPs, and other entities can easily match user IP addresses to search requests. Clear text search engine requests can be easily used to identify and eliminate political opposition and also ripoff intellectual property.
Here is an example of a typical Google clear text search query: http://www.google.com/search?hl=en&q=firstopenkeyword+secondopenkeyword+thirdopenkeyword&btnG=Search&aq=f&aqi=&aql=&oq=
Suggestion: Google, Bing, and Yahoo should use SSL to encrypt search queries to help protect their users from political harassment and intellectual property theft.