X111.com

Now here’s a great plugin I wish I’d discovered several years ago.
Smart 404 intercepts standard 404 messages and looks through your posts, tags and categories to see if it can come up with a match of what the visitor to your site was looking for. If it finds it, it will display it as a standard archive view displaying the posts.
Example: http://x111.com/azumanga doesn’t exist, Smart 404 however finds a tag for Azumanga Daioh and thus displays http://x111.com/tag/azumanga-daioh/ which is a HELL of a lot better than giving your visitor a blank ‘oops, it’s gone’ page.
If Smart 404 doesn’t find anything, at all, it goes to your standard 404 WordPress page, in which you can add some code to have Smart 404 generate a list of posts with the keyword a visitor was looking for (example). Again a big improvement.
I’m very impressed with this plugin, I only wish I’d have come across this years ago when I was moving all the old reviews into WP, that would have saved me from the big nosedive in daily traffic.

(download from the WordPress directory)