The majority of the top retail websites performed very well on Black Friday weekend. Congratulations to all of you, engineers, operations, devops, performance engineers, network engineers and everyone else involved!

Based on talks I had with various retail customers these past weeks, I knew most web sites would do well as everyone was well prepared. My only concern was with unknown third-party tags and what their impact would be on websites, during high traffic.

We have written about the impact of third parties, the gurus in the web performance space have run out of ink talking about it, and folks have lost their voice screaming about the wild performance of tags.

Amazingly this Black Friday, a relatively obscure third-party provider failed miserably on one of my favorite electronics stores, Newegg.  Here is the performance of Newegg since Nov 20 (Median by hour of about 3500 test runs):

Here is on Chrome Developer Tools while checking some amazing deals on SSD drives, augmented with some RUM (Real User Measurement) data:

The main reason this site’s page load degradation, was a pixel served by : “http://pix.esm1.net/am.php?idam=cf9dbbf9-7fd2-40f5-b43e-5ebb7060dfc2&id=CAESEEqhTsknLc_kY1YnKgbfFE8″ which belongs to a “Retargeting” company.

Here is now the performance of the “pix.esm1.net” host alone on the Newegg page, see how it matches Newegg’s spiky web performance:

The 3rd party’s web application could not handle the traffic generated by users visiting Newegg and other retailers. Clearly the company failed to scale their infrastructure properly.

Luckily for Newegg the retargeting tag did not have a visible impact on the user experience. The only loss for the retailer was with its retargeting campaign, it probably did not work as well as it should have.

That said, it is unclear what the impact was on other clients of the retargeting provider. If a web developer was relying on the “onload” event for any page functionality, the pixel would have definitely impacted the functionality.

Newegg still has time to take down the tag for Cyber Monday,… or have the provider scale up its infrastructure (maybe they can take advantage of their amazing deals and get some more servers).

Good luck.
Mehdi – Catchpoint