One of the things that keeps some users from using Google Search is the certainty that everything that is done on the site is being logged and analyzed by Google.
While it is possible to overcome this, for instance by launching searches only in the browser's private browsing mode, or using search engines such as Startpage that use Google search results but do not track you, you may prefer an automated solution that just works in the background without you doing anything.
You could try and use Google while you are not signed in to your Google Account, but that too means some form of tracking as there are other means besides tracking a user by account. Plus, it means that you cannot use other Google Services such as Gmail properly without signing in first again.
Another option would be to use two different web browsers, one for Google searches, the other for all other activities.
The new Firefox add-on Searchonymous introduces a solution that resolves this issue. It lets you search on Google without being seen as signed in by Google.
Even better, the search preferences are retained so that all custom preferences are still applied to the searches.
You can switch to other Google services and products, and will notice that you are recognized as signed in so that you do not have to sign in manually anymore.
In addition to all that, it removes advertisement and clutter from Google Search so that you can focus just on the results without being distracted by those.
The author of the extension explains how this is handled in detail.
Searchonymous helps to prevent your Google searches from tracking by Google or the NSA. When installed no tracking cookies are sent to Google while searching. This is done by blocking certain Google cookies (such as the PREF-ID) or generate randomized ones (which are worthless for tracking). Other cookies that just contain your search preferences will be allowed, so your preferences are preserved. You will stay logged in on other Google services such as Youtube or GMail. It also removes ads and clutter from the Google main page that is normally shown when cookies are disabled.
All source files of the project are available on GitHub.