I'm no $2,000 an hour social media expert from the bay but my guess is that it would be the same thing that keeps people engaged in the real world, useful/entertaining content. If a network posts on twitter about how their new debt settlement offer is converting at 20% then you'll probably make a note about it and move on about your day then promote it at whichever network will give you the highest payout on that offer. But if they post a big case study about how they started off with a 5% conversion rate and through ad/landing page tweaks and traffic optimization they were able to get it up to 20% then you would probably become "engaged" and bookmark the post, post a comment, remove your affiliate manager at that network from your AIM's blocked user list etc.