MrXHellboy

Track your 404 hits!
Do you keep track of your 404 not found hits ? If you don’t, try this simple plugin. 
It will keep track of the hits on your 404 not found page.
Useful for what ?
Well, probably you removed or relocated some categories, pages, posts etc etc a while ago or maybe just a couple of weeks without knowing anymore. 
Right now it sucks search engines already checked your website and took a notice of those URI’s or maybe you have some anchors on your own website pointing to moved URI’s. 
Those visitors arrives on your 404 not found page with a notice that the page they are looking for not exists anymore. 
Some visitors will stay on your site and look for the particular page, but the other group leaves immediately. What a shame…
What does this plugin do ?
This plugin tracks those visits on your 404 – not found page. It stores the time, requested URI and Referer. 
More information is absolutely not needed. The time and referer does already overdo it, but maybe you can get some extra information out of it. 
Thos information is stored in a txt file since i found it quite useles to create a new table or use the database in the first place. 
With 1 single click on the button you empty the file when you’re done with taking the appropriate actions on the results. 
You may want to add rewrite conditions @ your .htaccess file or use a seperate plugin for adding redirects. 
You can check the report within the admin settings menu – 404 report
How do i get it to work ?
Simple! 
1) Upload this plugin into your plugin directory. Activate the plugin: admin->plugins. 
2) Open your 404.php page within your theme and add the following snippet somewhere on that page. 
[php]
404 reporting
if (class_exists(‘NotFound_404’)){ 
 $Error404 = new NotFound_404(); 
 $Error404->Log404Error(); 
} 
[/php] 
3) Change the permissions (CHMOD) of the file 404.txt to 600.
Have fun logging!
<h3>Development Blog</h3>
<a href="http://online-source.net/category/scripts/wordpress-plugins/" title="Online-Source WordPress plugins" rel="nofollow ugc">Online-Source WordPress plugins</a>

404 Not found report

ReorMadrid

<h4>English</h4>
This plugin allows you to use one of your pages as a custom 404 error page. Most themes have a very basic 404 error page, lacking links or alternatives to help users find the information they were looking for. With this plugin, you can create a personalized page where you can add links or menus to keep visitors engaged.
No coding or programming is required. Simply install the plugin, activate it, select a page, and click the Save button.
This plugin is lightweight and features 100% transparent code, with no obfuscation.
Usage: Install this plugin and activate it. Go to Settings and open Easy Custom 404 Error Page. Select the page you want to use for 404 errors and click Save. That’s it—no further action is needed.
<h4>Español</h4>
Este plugin te permite utilizar una de sus páginas para convertirla en su página de error 404. La mayoría de temas tienen una página de error 404 muy básica, sin links y sin alternativas para localizar la información que se buscaba. Puedes crear una página personalizada donde puede colocar links o menús con el fin de retener esa visita.
No hay que programar ni tocar el código. Simplemente instalar el plugin, activarlo, seleccionar una página y pulsar el botón de guardar.
Este plugin es muy ligero y tiene un código 100% transparente sin codificaciones.
Uso: Instala este plugin y actívalo. Ve a ajustes y entra en Easy Custom 404 Error Page. Busca la página que quieres usar si hay un error 404 y pulsa en guardar. No hay que hacer nada más.

Easy Custom 404 Page

Customize your 404 error page very easy. Simply select a page and save.

404 Not found report vs Easy Custom 404 Page