QUOTE
* It tries to provide alternatives to incorrect URLs.
I would be impressed if it did this with any degree of accuracy. Maybe I was being too subtle, but I couldn't get the widget to offer me any alternatives at all.
For example, I tried http
://www.homeloanpartnership.com/network.htm, which doesn't exist, in hope it would suggest http
://www.homeloanpartnership.com/network.asp, which does exist. No luck. I also tried http
://www.homeloanpartnership.com/faqs.asp, but it didn't suggest the faq.asp page as I'd hoped it would. At that point, I gave up.
Basically, it's just a Google search box. And it's not even greatly helpful for that on a 404. Do a site search for
faqs, as it suggests, and nothing is found.

Thanks for the chance to test this, 1dmf.
I tried something similar to this almost ten years ago, with limited success. For example, try these links:
http://www.netpoets....ere/0001042.htmhttp://www.netpoets..../nothereanymorehttp://www.netpoets.com/life2These are all bogus links that return a valid 404 status, but in each case, the script has tried to figure out what the visitor wanted. In the first instance, the key is the page name; you can put in any path you want and so long as it terminates at 0001042.htm you'll be directed to the right location. In the second and third instances above, the key element is the folder. One is a repository for temporary pages that come and go and the other is an obsolete folder that is no longer used.
I think what Google's widget is claiming to do would be a really neat thing to have. I've always wanted to go back and try to increase the intelligence of my little script, but the law of diminishing returns kicks in pretty quickly. What I've done is pretty easy. Going farther gets much, much tougher. A lot of functionality could still be added.
I would love to have seen Google solve this problem for me. Unfortunately, it looks like they hit the same wall I did.