Well maybe Google's 404 Error Page Widget isn't that new, but I'm getting on in years and my journey across cyberspace isn't quite as swift as it once was. But it interested me anyway, because I know how pissed off 404 Error Pages make me.
Especially when they just pop up and hang their shouting blahhhhhh at you!
Of course the 404 Error Page Widget can be found in Google's Webmaster Tools.
This new "Enhance 404 Pages" allows you to embed a widget into your error page which will provide your user with suggestions and search functionality. That way your website visitor is less likely to leave your website, and more likely to continue browsing your website to find what they are looking for.
According to Expand Marketing, where I found out about this, this feature is experimental at this stage and will most evolve and develop as Google gets suggestions and comments. Get more information about the tool on Google Webmaster Blog
