Google has a search preference that allows a searcher to define how strict the adult filter should be. It is called Safe Search and I think it was originally designed by Matt Cutts.
In any event, I am seeing dozens of reports of the Safe Search filter getting "stuck." The largest standalone thread is at Google Web Search forums which describes the issue as users not being able to remove the safe search preference to something more lax.
Google Employee Skylar confirmed the issue in the thread and said they are looking into a fix. Skylar said:
Thanks for mentioning SafeSearch's odd behavior today. Several other people also commented on the same issue. I've passed this post, along with a few others, to our team so they can take a closer look at this.If anyone has more to add about SafeSearch not sticking, please include information about what kind of computer you have, what browsers are you seeing this problem in, what troubleshooters you've tried, and whether you have any filtering software. It will help me to best figure out what's happening here.
At about 2:30am (EST), this morning, Google seemed to have fixed the issue. I am not sure what caused it, because Google has not yet confirmed the fix, but we have at least two reports saying that issue is now resolved.
Forum discussion at Google Web Search.

Comments:
clethus archie
05/29/2009 07:31 pm
I am not able to turn off google safe search
caroline
05/30/2009 03:23 pm
Why can't I send a message directly to someone who will hear it? I have been trying to take "safe search" off my google filtering for what seems like a lifetime. I am getting so mad that I am about to take google off my computer altogether.
caroline
05/30/2009 03:24 pm
Does Google care? I don't think so.
messiah the 9inch master
05/31/2009 06:39 pm
Real bull$h*t I can't see any more naked women I didn't even turn this crap on I'm just a black dominican horny man that loves beautiful naked white,hispanic,arab and black women and watching them get pounded out why is this so hard to ask for.... Huh GOOGLE to hell with you :-p
Rob Abdul
06/01/2009 10:47 am
To Everyone: Quiz your Windows / Anti-virus program to evaluate whether cookies are being blocked.
Michael Enfantino
07/25/2009 07:09 am
My safe search filter is stuck on
brianna
07/26/2009 12:05 pm
my damn safe search wont fucking come off
levi
09/23/2009 02:17 pm
i have been up all nite trying to take safe search off my toshiba laptop but i cant see anything that can help me
Les hat
09/25/2009 09:01 am
Google safe search still stuck I cant see any thing that will help
David
09/28/2009 03:09 am
I have an HP laptop and cannot turn off the Safesearh on Google, Yahoo, or Bing. It is still sticking.
Anil
11/06/2009 05:04 pm
type dove in search keyword and set search filter to strict i got photos of women posing in underwear. some filter!!
Dave
01/12/2010 07:42 pm
Don't use Google to search. Use Yahoo.
richard
03/16/2010 05:27 pm
i think that students should be able to take of googles safe surch
jonathon
05/25/2010 06:32 am
ITS NOT LETING ME ON FACEBOOK ITS so bad
john
05/26/2010 04:22 pm
i did not ask for or install safe search. it is on my computer illegally, and DOES NOT provide an option to turn of or dis-install. thanks a bunch for the invasion of privacy!
greg
05/30/2010 11:10 pm
cant turn safe search off !
Leo
06/03/2010 12:09 pm
How can i remove safe search from google.I think so google does`nt care.Now I can not search anything i want.
Rob
06/03/2010 12:11 pm
now i can not any porn video or anything.i can`t search sexuall things now what to just fuck off!
Rob
06/03/2010 12:12 pm
now i can not search any porn or sexy girls or videos.How can i remove google safe search i gone mad.
Dan Pesonen
06/15/2010 01:07 am
My safe search just got stuck to strict. On all search engines What gives???
don long
07/04/2010 04:07 pm
Safe search is stuck and wont shut off no matter what I try.
don long
07/04/2010 04:14 pm
Maybe we neeed sue Google or file complaints againts them with the FED's.
Mike
07/22/2010 08:47 am
I have just noticed it has happened to me too! It looks like it is going to seriously interfere with my SEO work as I am unable to get an accurate idea of how my Web images rank in Google when researching my Keywords (such as tibetan tattoo etc.) That this should still be going on more than a year after the initial reports is simply ludicrous..
Zebulon Virginia
11/23/2010 04:01 pm
Google safesearch is stuck on moderate. I'm using a MetroPCS LG Imprint. Has a solution/workaround been found? I'll try Yahoo instead. 23 Nov 2010.
Mike
11/25/2010 12:26 am
This is really pissing me off! Fix this bullshit, Google!
Angry
12/24/2010 06:23 pm
Well, almost two years has passed, and it's NOT fixed. ¬_¬
Xxx
02/08/2011 06:08 am
Its not fixed. 2 7 2011 and it still sticks on my so called smart phone no matter what I try to resolve the problem. This did the same thing on my last android phone as well.
Vanderpuch
08/15/2011 02:45 pm
Today my new computer censors google searches. Dell with windows 7. My old computer Dell running on windows me allows more raunchy pictures. how do I fix this?
Omegaten
12/13/2011 10:24 am
Oddly, though Google SAYS Safe Search is off, it never actually seems to be off. Unless I'm deliberately searching something that wouldn't get any non-filtered results, I get pretty much nothing coming up -- even something as simple and obvious as "hot," which would have got a bunch of porn results back in the day, came out with no more than one on the first three pages. (And yes, I made a lot of juvenile Google searches to test this. My ISP probably thinks there's a horny and confused 12-year-old living here.)
Ratdass
01/16/2012 12:12 am
It is NOT resolved!!!
Ratdass
01/16/2012 12:15 am
Pure censorship... police state! WTF#$&*!!!!!
44travis1977
01/16/2012 06:51 am
Seriously....not resolved. Wtf...
adriespo
01/22/2012 10:22 pm
Still not resolved
Catatonia
01/24/2012 10:28 pm
I still can't get the search settings to stick....i use google chrome but it does the same thing with IE and Firefox also. But I CAN get the search settings to save in other search engines (such as yahoo)
Sophia
02/17/2012 12:21 am
PLEASSEEEEEEE SOMEONE HELP I AM A WINDOWS 7 OWNER AND GOOGLE SAFE SEARCH IS IN THE WAY ! HELPPP !
Jackle
03/06/2012 03:39 pm
any idea as to why it is still sticking. i can't turn it off on my computer or my phone and its highly annoying. help me out here or just simply fix it google!!!!!!!!!!!
Rook
07/27/2012 06:07 pm
On iPhone, go to Google, switch to Classic (full website) here you will be able to see your setting are on Strict, and you can change them and they will stick. Fucking Google!
PIssed Off
08/14/2012 04:02 am
It's STILL not fixed. Suck it google!