Trademark expert witness (in keyword advertising):  A trademark expert witness in the area of keyword advertising (such as in Google AdWords) will conduct technical analysis in order to provide an opinion concerning the use of a trademark in search engine advertising or marketing, which is the a online advertising model in which advertisers' ads are associated with certain words on search engines, the ads can appear when a person searches with those words, and the advertiser pays the search engine when the person clicks on the ad.

A trademark expert witness in the keyword advertising area can address a wide range of analysis, including whether or not a trademark was used, trademark infringement, the revenue generated, the revenue harm if trademark infringement occurred, and how trademark infringement occurred among many others.

 Bernard J. Jansen, Jim Jansen, Jansen Expert Witnessing (current as of 2024)​