I just received an email from both Delta and United, stating they would discontinue their shopping toolbars on January 10, 2013. While United gave no reason for this, Delta offered the following explanation:
Ultimately, overall adoption of SkyMiles Shopping Assistant by our SkyMiles Shopping customers was less than we anticipated, and it will be unavailable as of January 10th, 2013. We apologize for any inconvenience this may cause you. Any miles earned via shopping or searching via SkyMiles Shopping Assistant through January 9th, 2013 will be honored.
While the shopping function isn’t a huge loss, since you can still earn points through their shopping portals, this means no more miles for searching. Not a huge loss, but this is one less activity you can rely on to keep your miles from expiring.