A “404″ page is the page a visitor to your website/blog sees if they try to visit a page that does not exist. For instance: http://inventblog.com/ 1234234213.
Most websites have a boring 404 page that merely says “page not found, sorry.” Sadly, that rarely helps your visitor find what they were looking for.
Why not do what Google recommends and “Make your 404 pages more useful” by installing a simple script on your 404 page that includes a Google search widget, a widget helps your visitors find what it was they were looking for? It’s too simple to not do.