You can call them tracking pixels, clear gifs, 1x1 pixels or web bugs. They have been in use for almost as long as cookies have been used to collect and store data about visitors to your website. In this, the era of big data and cross-channel analytics, tracking pixels seem like a terrific way to obtain the in-depth information that you need to assign attribution or offer visitors a personalized experience or provide that Holy Grail report you’ve been pitched from the latest company to contact you about the latest & greatest tracking technology. Used properly — meaning used in moderation — tracking pixels can fulfill their function well. The problem is that marketers tend to overuse tracking pixels to the extent that the site's performance is negatively impacted and tracking data is siloed across many different tracking pixel providers.
What Tracking Pixels Are
Tracking pixels are small images, typically 1 pixel by 1 pixel, that are placed on website pages. They are often transparent for complete invisibility, but their tiny size means that few visitors would notice them even if they are opaque.
How Tracking Pixels Work
Normally, a line of HTML code is placed on the website that specifies an image tag. The visitor's browser recognizes the code and sends a call to the server that is hosting the image, which is normally the server of a third-party domain. This call can transfer information, such as the visitor's order total or other details, as an HTTP request. Upon receiving the request, the server transfers the tracking pixel.
Where Problems Arise
You might have already spotted two issues with tracking pixels. The first is that they must make a call to the hosting server. The second is that tracking pixels are image files. HTTP calls and images can both slow down the speed with which your pages load. It’s just one little pixel, right? How can this hurt anything? Multiply this by 6 or 12 or 18 and you’ll quickly see a difference in your site performance.
Why is This Important?
In the early days of the Internet, users expected sites to load slowly. Modem speeds were 28k or 56k, so some people referred to the Internet as the "worldwide wait." There were jokes about going to the kitchen to make a sandwich and having it half-eaten by the time a requested page loaded.
By 1999, research indicated that up to one-third of your visitors would leave your site if your page took more than eight seconds to load. Seven years later, studies showed that 33 percent would bail if the site took more than four seconds to load. A study of online shoppers conducted in 2009 found that they expected websites to load in no more than two seconds, and they left in large numbers at three seconds. Amazon conducted tests in 2007 that indicated that sales dropped by 1 percent for every 0.1 second increase in page loading time. The previous year, Google discovered that increasing search results from 10 per page to 30 required only 0.5 seconds longer — but resulted in a 20 percent drop in traffic.
How Marketers Overuse Tracking Pixels
Marketers typically have numerous campaigns running simultaneously. Naturally, they need to know how successful each campaign is performing. They can place a tracking pixel for each campaign on the conversion page, for example, to send them real-time data on each. Alternatively, they may want to collect data at other points along the customer's purchase journey, such as identifying customers who have placed items in their carts and then abandoned the site, or customers who made it to the checkout before leaving, perhaps because they did not have or preferred not to use the payment options. Imagine how frustrated customers could become if you had a dozen or more tracking pixels on each of several pages of your website that were loading slowly.
What is a Better Solution?
The better solution is an enterprise analytics program that has been well-configured and properly implemented. Google Analytics can provide the basic information you need, but a solution such as Sitecore xDB can give you the data you need to identify each specific person. Properly configured and implemented, an analytics program will not impact the performance of your site the way that tracking pixels can.