This is surprisingly difficult for enterprises to keep track of. Different divisions might have different websites, or different campaigns running, and be placing things like tracking pixels or tags all over the place without telling anyone.
And embedded content can come with trackers of their own. For example if you embed a Storify feed in your site, you get 4 trackers with it. Surprise!
They'll host a page for the enterprise that lists out all the trackers, and gives visitors opt-out links for each one. Again--a total pain for most companies to try to do themselves.
It's all powered by people running the plugin, but the plugin data not what's for sale. At least, they never pitched me on it, and it's not part of their service description on their website.