Why are the links different in emails sent from Flickr?
The links in emails sent from Flickr have an extra bit in the middle of the URL to let us know how effective they are so we can keep making Flickr better. Here’s an example of what the URLs look like: http://www.flickr.com/x/t/0107002/photos/customURL/ This lets us count the number of clicks from the emails and the type of link it was (ex. a photo, photostream, group, etc.) and that’s it! Nothing about the click is associated to your account or the account it links to in any way.
