We have volunteered to take up the maintenance of a very useful Drupal module - Search404. As of today we are the official maintainers of this very useful Drupal module. We know that this is going to be a challenge for us, being a young company and with a young team. But we do feel that it is our responsibility to give back to the Drupal community at least some part of what it has given us.
About Search404 Module
Normally when a user types in an incorrect URL in a site the web server will issue a 404 error (page not found error) and correspondingly redirect you to a 404 error page. If there is no custom 404 page on the server the browser will show the 404 page not found error to the user. This could happen when either the user types in the URL himself or he clicks on a URL incorrectly typed in another page. Another case when such errors happen is when content is deleted or moved in a site and the search engine indices have not been updated to reflect the removal or change.
The web crawlers of search engines on getting a 404 error will take out the URL from their indices. The normal web user will however be totally lost when he sees the 404 error page. This is especially true if the user came from a search result page and has no idea about the navigational structure of the site or the content organization of the site.
Drupal however shows its own 404 error page and avoids showing the grotesque, default 404 page that would otherwise be shown by the browser to the end user. Even this 404 error page is only a bare page with just the information that the page cannot be found. The Search404 module intelligently does a search for the terms in the URL while still issuing a 404 error. This will ensure that the URL gets taken out from the search engine index at the same time making sure that the user is given some options in terms of navigating in the site.
You can check out how this works by clicking on the following non-existant URL Drupal Modules from Zyxware. Even though the page does not exist you get what you wanted to get to. If you have any questions, issues or suggestions regarding this module you can either post them as comments to this page or post your issues at the Search404 Module at Drupal.org.