The point is just that, creating good error pages is the last thing anyone wants to spend time thinking about or doing. So this streamlines that.
It's a shame because after reading the explanation you give for your service, this is something that IS extremely useful with a low bar of entry. Please update the site as I would hate to see you lose revenue.
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I need to have a valid reason to register to a website and usually "to find out what the website does" is not one of them.
I'm just saying that an explanation on what this service does and how it works before the need to register for it would be nice.
That's the (for me) interesting part but there are no signs of any of that on the website.
Probably if I register everything will be explained to me, but let me know what I'm registering for before I do it out of blind faith.
That said, if you do register, you can click your email account to modify how many request a page must receive for you to be alerted.
You probably should offer a bit more information. After all, you're targeting this at technical users, the barrier for entry doesn't have to be that low. Particularly since the service you're offering is "trust me to redirect your users with javascript whenever your site messes up."
I also agree I need to add more information. The javascript isn't redirecting at all though - just dynamically loading the page in the static error page.