Measurement of Trackers

Count of third-party (TP) scripts by site and category
Overall, we found 2609 third-party (TP) scripts in the 138 websites that we crawled. 1446 (55%) out of 2609 are categorized as trackers, 78 (3%) as advertisers, and the rest are unknown. The top 4 most frequently detected trackers are,,, and

Count of third-party (TP) cookies by site and category
We found an overall of 2487 TP cookies in the 138 websites we crawled. 931 (37%) are categorized as trackers, 708 (28%) as advertisers, and the rest are unknown. The most frequently detected tracking domains that have set TP tracking cookies are , followed by, then E.l.f Cosmetics has the largest number of TP cookies, 121: 40 of which are trackers, and 56 are advertisers (the rest are unknown). Other popular brands such as Eyeconic25 and Lenscrafters26 for eye-wear have 45 and 41 TP tracking cookies, respectively.

Expiry dates statistics for every third-party (TP) cookie host domain
We found several TP tracker domains which set cookies with expiry dates to the year 9999. For example, and have each set such tracking cookies in 16 websites. In the crawled websites, a total of 55 out of 931 (6%) TP tracking cookies are set to the year 9999, 0 to more than 5 years but not 9999, 403 out of 931 (43%) to more than 1 year but less than 5, and 358 out of 931 (38%) to more than one month but less than 1 year.

Tracking libraries in Android apps
We found 19 distinct tracking libraries in the 28 Android apps we tested. The following figures summarize our findings. The figure on the left shows the overall frequency of identified tracking libraries in tested apps. The figure on the right shows the number of identified tracking libraries for every app