In collaboration with the Internet Archive, human coding and machine tracking was used to identify all 74 political ads that ran on 7 major television stations in the Philadelphia market September 1 to November 4, 2014, which were coded for acclaim/attack/defend tone, a transcript entered, and the sponsor who paid for each of the 13,675 airings of the ads was determined. You can drill through all of this via an interactive visualization, doing things like comparing the ads about a candidate that were paid for by that candidate vs his/her opponents. You can also view all 74 ads in order from most positive to most negative.

Read the Official Announcement on the Internet Archive Blog.
View the Interactive Visualization.
View All 74 Advertisements.