[standupstandup]

That's not clear at all. Do you think the Twitter founder's goal was literally written down somewhere as "manipulate users to engage with it"? Or for Facebook? None of these companies will agree with that assessment, so it's entirely your own subjective opinion.

[addicted]

Well, the interviewee in the article provides a good metric.

You don't need to look at the founders' intentions. You simply need to look at the metrics they are optimizing on. For public companies like Facebook and Twitter it's even easier. You have to look at the metrics they are talking to their investors about.