"They could tap the line upstream of the provider, and just look for packets containing www.google.com/search. Next to this are your search terms in plain text, with your IP address in the same packet"

Thats just one example of just how unsecure Google is, and here is another.

"Most employers monitor the websites visited by their employees. There are impressive "employer spyware" packages such as Websense that they use to do this. Because the GET method is preferred by almost all search engines (see this page), even if the employer sees only the web address that you used to arrive at Google, he already knows the search terms you requested. With a record of all the search terms you've used while you were at work, each with a date and time recorded in his log, your employer has a pretty good idea of what you've been thinking. There are no laws that prevent employers from doing this sort of snooping"

Full article at source.