  We present Tracking Protection in the Mozilla Firefox web browser. Tracking
Protection is a new privacy technology to mitigate invasive tracking of users'
online activity by blocking requests to tracking domains. We evaluate our
approach and demonstrate a 67.5% reduction in the number of HTTP cookies set
during a crawl of the Alexa top 200 news sites. Since Firefox does not download
and render content from tracking domains, Tracking Protection also enjoys
performance benefits of a 44% median reduction in page load time and 39%
reduction in data usage in the Alexa top 200 news sites.
