I was under the impression this was mainly to track user engagement for ad networks and search engines. Navigating to a page and leaving it open doesn't rank as highly for engagement; navigating to a page, scrolling through an article (which contains possible ads), and skipping back and forth between the ingredients list, steps, and explanatory text, is interpreted as higher engagement
This discussion is following every discussion of online recipes. Let me add my own argument: When I am looking for a specific recipe I am not interested in the extra content. However, when I am following a person's recipe blog I want to have that extra content. Having just a feed of recipes is just not that interesting as a collection of stories and accompanying recipes. The stories make it personal and it's nice to get glimpses into the life of the person doing the cooking. As a blogger it's also more fun to share more than recipes - you are writing a blog after all, not just a cookbook. If the ad revenue rises as a result of that - it's a nice bonus.
