Seth Schoen writes:
One great trend for Internet users’ privacy and security has been that search engines — among other popular sites — are making their services available in a secure HTTPS form.
But users can still run into a privacy problem when they click on search results: the destination page could be unencrypted, potentially revealing lots of information to eavesdroppers about a user’s interests and activities. For instance, suppose you search for [coronary artery disease] on a search engine, and you click on the search engine’s outbound result link to Wikipedia’s page athttp://en.wikipedia.org/wiki/Coronary_artery_disease. Even if your connection to the search engine was protected by HTTPS, your connection to Wikipedia won’t be!
Read more on EFF.