A 404 page is what a visitor to your site will see if they follow a broken or dead link. For example, last week you participated in a blog hop. One of the requirements was that you link up a post from your site about a new recipe. While linking up your post at www.mysite.com/newrecipe, you misspelled it and put www.mysite.com/newresipe. So when someone clicks on your link they will see a 404 page a bit like this:
Almost 98% of the time, when someone comes to a broken link on your site, they immediately leave. Which increases your bounce rate. Most people don't think to click on another page and search for the information they were seeking.
A custom 404 page will better the odds of them staying. You can add a variety of things on it. From search boxes to site maps. I've kept my simple so far, just providing an explanation and a link to my Home and Contact pages.
Blogger requires you to add a HTML custom 404. Follow these steps to easily create one.
First, you need to create the custom HTML. To do this click on the pencil button from your Blogger Dashboard like you are creating a New Post.
In the top left of your screen, you will see Compose and HTML
While in the Compose method, type whatever you want your custom 404 page to say. Once complete, click on the HTML method, then select it all, right click on your mouse and copy it.
NOW, from your Blogger Dashboard, go to:
In the middle of the page you will see Errors and redirections
Next to Custom Page Not Found, click on Edit and the above area will expand like shown and paste your HTML here. Then click Save changes.
To test your 404 page, you can type in a url that you know isn't in your site. Like this: www.bloggerblackboard.com/test404.
Let me know when you've finished your Custom 404 Page. I'd love to swing by and see how creative you are.