Abstract
Cookie banners are devices implemented by websites to allow
users to manage their privacy settings with respect to the use of cookies.
They are part of a user’s daily web browsing experience since legislation
in Europe requires websites to show such notices. In this paper, we carry
out a large-scale study of more than 17,000 websites including more than
7,500 cookie banners in Greece and the UK to determine compliance and
tracking transparency levels. Our analysis shows that although more than
60% of websites store third-party cookies in both countries, only less than
50% show a cookie notice and hence a substantial proportion do not
comply with the law even at the very basic level. We find only a small
proportion of the surveyed websites providing a direct opt-out option,
with an overwhelming majority either nudging users towards privacyintrusive choices or making cookie rejection much harder than consent.
Our results differ significantly in some cases from previous smaller-scale
studies and hence underline the importance of large-scale studies for a
better understanding of the big picture in cookie practices.
