A 2003 report by Harvard Law School's Berkman Center for Internet & Society stated that SafeSearch excluded many innocuous websites from search-result listings, including ones created by the White House, IBM, the American Library Association and Liz Claiborne. On the other hand, many pornographic images slip through the filter, even when "innocent" search terms are entered. Blacklisting certain search terms is hindered by homographs (e.g. "beaver"), blacklisting certain URLs is rendered ineffective by the changing URLs of porn sites, and software to tag images with copious amounts of flesh tones as porn is problematic because there are a variety of skin tones and pictures of babies tend to have a lot of flesh tones. Google's ability to filter porn has been an important factor in its relationship with the People's Republic of China.
On 11 November 2009 Google introduced SafeSearch Lock, which allows users with Google accounts to lock on the "Strict" mode of SafeSearch in Google's Web, image and video searches. Once configured, the user can log out of their Google account and the setting will stick to prevent any change to the filtering level.
- Benjamin Edelman (April 14, 2003). "Empirical Analysis of Google SafeSearch". Harvard University. Retrieved 3 February 2013.
- "Canada's The Beaver magazine renamed to end porn mix-up". AFP. January 12, 2010. Retrieved 3 February 2013.
- Paul Festa (July 2, 2001). "Porn sneaks past search filters". CNET News. Retrieved 3 February 2013.
- Owen Fletcher (September 6, 2009). "Google Porn Filter Gained China's Thumbs-up". PC Word. Retrieved 3 February 2013.
- Pete Lidwell (November 11, 2009). "Locking SafeSearch". Google Official Blog. Retrieved 3 February 2013.
- Dino Grandoni (12 December 2012). "Google Porn Just Got More Difficult To Search For". Huffington Post. Retrieved 3 February 2013.
- Casey Newton (December 12, 2012). "Google tweaks image search to make porn harder to find". CNET News. Retrieved 3 February 2013.
- Matthew Panzarino (12 December 2012). "Google tweaks image search algorithm and SafeSearch option to show less explicit content". TNW. Retrieved 3 February 2013.
- Josh Wolford (December 16, 2012). "Google No Longer Allows You to Disable SafeSearch, and That Makes Google Search Worse". Web Pro News. Retrieved 3 February 2013.