United MileagePlus and points.com
It appears to go well beyond what you are seeing. As of several days ago, accumulated miles from a MileagePlus account no longer appeared on the points.com landing page, and adding a MileagePlus account was no longer an option.
With this development—and, the fact that Southwest Airlines and points.com do not have a relationship which allows a flyer to track miles—I find that their site is losing substantial value as a tracking tool. Who will next drop off the summary page?