If you happen to type a web address on Google that doesn’t exist (e.g., google.com/yahoo, google.com/adsence), you are no longer shown the default 404 Error Page that says "The requested URL was not found on this server."
Since errors like 404 are like greek to most people, Google is taking a more user friendly approach and they now try to guess the page you are looking for.
For instance, if you type google.com/email, it suggests you the Gmail website instead of displaying the regular "Page Not Found" error.
Similarly, a typo like google.com/blog will throw in suggestions pointing to the Google Blog Search Engine. A very neat approach.

Update: You will still see the same old 404 page on Google if your erroneous URL has a file extension (like google.com/labnol.html or google.com/secret.php)
Related: AdSense Publishers may show ads on 404 Error Pages according to the recent AdSense Policy changes.
Find this article at: http://www.labnol.org/internet/design/google-404-page-not-found-custom-error-intelligent-useful/2757/
Tags: 404, Archives, google, page not found, Internet, Web Design
Reader Comments
Doesn’t do that for us. Probably you are using the new version of google toolbar ???
Written by Tech Bytes on 03.30.08
You seems to find these things before everybody else does (including top blogs). Great job.
However, In my testing I found the same old 404 error page. I tried the same url as yours. Probably, Google is still trying it.
Written by abhilash on 03.30.08
I cant see any changes yet. :(
Written by Archit T on 03.30.08
Did you try any of the following Google addresses:
1. link
2. link
3. link – this should suggest the official Googleplex domain and the Google CSE page (Custom Search Engine)
Written by Amit Agarwal on 03.30.08
Does not work for me either – tried all your 3 examples and I still get the old:
Not Found
The requested URL /email was not found on this server.
Written by Klaus on 03.30.08
I think you are getting confused with a google search feature — if a specific page you are looking for is not found, then google search tries to be helpful and some of the suggestions may infact be what you are looking for.
And in browsers that default to searching for a page that does not show up and if google is the configured default search engine and perhaps if google toolbar is installed, then the 404 error results in a google search for the page you were looking for.
Written by Sanjay S on 03.31.08
Sanjay – this is not connected with Google Search. This is about pages and directories hosted on the Google.com domain.
Have uploaded few more screenshots on link .
Written by Amit Agarwal on 03.31.08
this seems to be another move of Google to provide better services to users . Does the same work with Google’s Service-domains , like : Orkut and analytics ??
Written by ArpitNext on 03.31.08
None of the 3 URL’s work the way you said it would.
It is the same old
Google Error
Not Found
The requested URL /email was not found on this server.
Written by Ajay on 03.31.08
same here Amit
none of the URL’s are working for me too…??
why is it so that only your system is showing the changes..??
Written by CompuWorld on 03.31.08
I got it working now. I think it is taking time to reflect the change in all the locations.
Written by abhilash on 03.31.08
luck for you find this… but its not work for me.
Written by Luis on 03.31.08
Hi Readers,
This only works with new Google Toolaber Beta 5.
this feture is available from last 6-7 months.
cheers
Written by Bhangu on 03.31.08
Matt Cutts issued a “clarification” a month or so ago regarding this toolbar function.But this is entirely different since I dont have the toolbar version installed
Written by Network Weblogs on 04.03.08
I have Internet Explorer and since today every time I’m looking for something in the Google bar this message appears “Google error the request URL was not found on this server” How can I fix that… I can’t search anything cuz everytime I’m looking for something that message appears
Written by Aldo on 07.13.08
I tested the URL you used, and I get the new error message, but it doesn’t suggest any sites.
Written by Tim on 08.24.08
I am going to a website I know exists – it is my yahoo account. It will show the page for a couple seconds and will then throw me onto the old error page. I have tried backing up and reaccessing the site, but it keeps throwing me back to the error. Any suggestions?
Written by Julie on 08.26.08