Indeed, but the opportunity of that control also carries the potential for ruin. Skew the algorithm for maximum profit and the result is less long-term revenue

Indeed, but the opportunity of that control also carries the potential for ruin. Skew the algorithm for maximum profit and the result is less long-term revenue thanks to a reduction in usefulness to the user, which leads to either inattention or abandonment... no eyes, no ads. Providing user control (even limited) over the newsfeed actually increases leverage with regards to long-term revenue, since it's an expression of user intent... which is a clear datum for targeting. What it dampens is the kind of "run of site" or "simple demographic" advertising that sites often accept because it's "found money!" Except that in the long-term it isn't, due to inattention/abandonment problem mentioned earlier.