Just last week I came across a site that listed over 1500 "partners". I' wonder if anyone from that company can tell me who each of those is and what they are used for?
This is because you have one vendor who does a specific task (ie audience matching for a data management platform or third party audience vendor) and that vendor uses tens/hundreds of vendors to power their product. So you place a single 1x1 image pixel, but that can call one of many different scripts.