When you visit a popular website you will be confronted with ads and trackers. We all know that these ads and trackers are installed by the website publisher to make money and track our behaviour. What you probably didn't know is that ads and trackers themselfs can on also load new ads and trackers. As from UltraBlock 1.4.1 (may 2018) you can now also see what service are initiated by another service.
When the publisher of a website installes Google Analytics the code is loaded directly via the HTML of the publisher. In other words the publishers website is the initiator of the Google Analytics script. But when a publisher installs a service like DoubleClick (Google product) then DoubleClick will also load: Google Syndication ,Google Static, 2MDN and sensic.net. In this case the initiator is DoubleClick and not the website of the publisher.
When you open the UltraBlock pop-up and click on a service you'll see the label Initiator. This shows what the initiator of the service is. If a service was initiated by another service and not the website you're visiting we'll show a '➞' in front of the service in the service list.
If the selected service is an initiator itself (like the DoubleClick example), then there will appear a label called Initiated. The Initiated label shows what services the selected services initiated. So in the DoubleClick example you will see the services Google Syndication, Google Static, 2MDN and sensic.net appear in the list. This gives you great insights in what is loaded by who.
In the service list we also display how any other services are loaded by the service. If a service loads five other services then UltraBlock shows a | 5 ➞ behind the service. Just visit a big, popular new website like cnn.com, venturebeat.com or techcrunch.com and turn off UltraBlock to see the magic.