  The Real Time Bidding (RTB) protocol is by now more than a decade old. During
this time, a handful of measurement papers have looked at bidding strategies,
personal information flow, and cost of display advertising through RTB. In this
paper, we present YourAdvalue, a privacy-preserving tool for displaying to
end-users in a simple and intuitive manner their advertising value as seen
through RTB. Using YourAdvalue, we measure desktop RTB prices in the wild, and
compare them with desktop and mobile RTB prices reported by past work. We
present how it estimates ad prices that are encrypted, and how it preserves
user privacy while reporting results back to a data-server for analysis. We
deployed our system, disseminated its browser extension, and collected data
from 200 users, including 12000 ad impressions over 11 months.
  By analyzing this dataset, we show that desktop RTB prices have grown 4.6X
over desktop RTB prices measured in 2013, and 3.8X over mobile RTB prices
measured in 2015. We also study how user demographics associate with the
intensity of RTB ecosystem tracking, leading to higher ad prices. We find that
exchanging data between advertisers and/or data brokers through
cookie-synchronization increases the median value of displayed ads by 19%. We
also find that female and younger users are more targeted, suffering more
tracking (via cookie synchronization) than male or elder users. As a result of
this targeting in our dataset, the advertising value (i) of women is 2.4X
higher than that of men, (ii) of 25-34 year-olds is 2.5X higher than that of
35-44 year-olds, (iii) is most expensive on weekends and early mornings.
