http://www.sendgrid.com/ http://www.sendgrid.com/ which provides email services to a lot of clients perhaps uses this by default. I don't think people in this b

http://www.sendgrid.com/ http://www.sendgrid.com/ which provides email services to a lot of clients perhaps uses this by default. I don't think people in this business look at it as an attack. Websites use various techniques to track people's activities, and this is just another one of them.