It's never a good first impression when a new user comes to your site and gets an 'error 404 page not found'. This can happen for any number of reasons; URL typo, index problems or just bad template coding. These errors can happen to any of your site viewers, not just new ones, but until you can get around to sorting your URL directories out it's always a good idea to create a custom 'page not found'.
Bloggers default message is displayed within your templates header and footer post section. The generic message is a bit basic and plain especially by not having Cascading Style Sheets aka CSS.
