I think it is helpful to write regularly - I aim for one piece a day or at least an average of 30/month. I find that readers want reliability - they may see my content, but if they don't see it again for a while, they may not come back. I've also noticed that taking more than a couple days away from publishing results in a dip in views/reads. So, if I know I'm going to be out (vacation, etc.), I try to write several pieces and schedule. My experience with curation is similar to yours - I see a nice bump, then it fades. I've also had some stories get great external reads from ranking high in Google even though those pieces weren't distributed. The other correlation - my engagement rate and the number of actual reads on my stories.