What is a "Redirect loop"?

Gmail is upgrading their contacts feature, so just log back in in 5 minutes and everything will be back to normal.

A redirect loop is where the site has been programmed to redirect in a loop that will never end. Firefox usually detects it and stops it from happening.

A redirect loop is when a website is redirecting you to a site which then redirects you back to the original site, creating an infinite loop.

http://en.wikipedia.org/wiki/URL_redirection#Redirect_loops

@wgallios Google Chrome does too, apparently.
Thanks everybody!

What is the purpose of redirect loops? When a webmaster programs one, what exactly is he trying to do?

Well it’s really something you would want to avoid. Usually It’s a bug. In this case I believe it’s a result of google upgrading their big, complicated system.

@Kraigmo Probably to keep the site refreshing. In this case if a user visits the site just a few moments before the service has been upgraded he won’t have to refresh the page on his own, but will be redirected to the working page by the webpage itself.
I’m guessing, but that’s why I would make it.