TThere may be hope in protecting your online activities. Scientific Blogging reports that researchers have

. . . developed a new protocol based on cryptographic tools to distort the user profile generated by internet search engines, in such a way that they cannot save the searches undertaken by internet users and thus preserve their privacy.

There is a more detailed report at EurekAlert. An excerpt:

Search engines such as Google, Yahoo and Microsoft Live search save the profiles of their users (via an analysis of the searches they undertake) with the argument that they are more familiar with their interests and offer a more efficient response.

There currently exist types of software which provide anonymous navigation, such as the Tor network, but the new system “offers a clear improvement in response time”. Nevertheless, Alexandre Viejo acknowledges that the application of the protocol delays searches slightly, “but it can be perfectly assumed by the user”.

An abstract of the article can be found here; the article itself is behind a paywall, as is common with scholarly journals.

The technology does not yet appear to be publicly available.