Why do links in gmail redirect?

Question

I've noticed that some email services (like gmail or my school's webmail) will redirect links (or used to) in the email body. So when I put "www.google.com" in the body of my email, and I check that email in gmail or something, the link says something like "gmail.com/redirect?www.google.com".

This was very confusing for me and the people I emailed (like my parents, who are not familiar with computers). I always clicked on the link anyway, but why is this service used? (I'm also worried that maybe my information was being sent somewhere... Do I have anything to worry about? Is something being stored before the redirect?)

Sorry if this is unwarranted paranoia. I am just curious about why some things work the way they do.

Answer 1

Wikipedia has a good article on URL redirection. From the article:

Logging outgoing links

The access logs of most web servers keep detailed information about where visitors came from and how they browsed the hosted site. They do not, however, log which links visitors left by. This is because the visitor's browser has no need to communicate with the original server when the visitor clicks on an outgoing link. This information can be captured in several ways. One way involves URL redirection. Instead of sending the visitor straight to the other site, links on the site can direct to a URL on the original website's domain that automatically redirects to the real target. This technique bears the downside of the delay caused by the additional request to the original website's server. As this added request will leave a trace in the server log, revealing exactly which link was followed, it can also be a privacy issue.1 The same technique is also used by some corporate websites to implement a statement that the subsequent content is at another site, and therefore not necessarily affiliated with the corporation. In such scenarios, displaying the warning causes an additional delay.

So, yes, Google (and Facebook and Twitter do this to) are logging where your services are taking you. This is important for a variety of reasons - it lets them know how their service is being used, shows trends in data, allows links to be monetized, etc.

As far as your concerns, my personal opinion is that, if you're on the internet, you're being tracked. All the time. If this is concerning to you, I would recommend communicating differently. However, for the most part, I think it's not worth worrying about.

Answer 2

This redirection is a dereferrer to avoid disclosure of the URL in the HTTP Referer field to third party sites as that URL can contain sensitive data like a session ID.