The API is free but subject to acceptance of our License Agreement. The philosophy is to provide full functional parity of what users see within MyFeeds and our widgets.
If you consume a lot of web content daily, you’re always seeing rehashes of stuff you’ve seen a million times. If I check my NYT tech feed, then I want a tag that says “New!” on the article whose substance is new. If it’s just a rehash, then no tag.
There is an inverse relationship between a social media service’s “affinity,” the average closeness of relationship between a content creator and viewer, and its targetability, driving the wide divergence in CPM rates. “Herding” also hurts targetability.