This is wrong– people do notice, and it’s usually the early adopters. The cost benefit here is that you can reuse content to increase metrics but you end up decreasing the quality of the experience for the early set that got you to mainstream. This is the way products go through their product life cycle:
no one even seemed to notice that we were flooding the site with previously published content. A lot of the articles were enthusiastically shared by people who had shared them the first time around, too. No one seemed gripped by a sense of deja vu, or, if they were, they didn’t mention it.