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 generating 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.
Please note that even if no tracking cookies are sent the NSA can possibly try other techniques to track you (e.g. by IP or browser headers) but these are not as accurate as tracking IDs that are sent on every search.
If you would like to donate in Bitcoin, feel free to send them to:
--------------------------Project on Github
This addon uses code from the great No cookie for Google search