I don't know but it seems like a poor article. From what I know, every time you write an Idea, you should always conclude it with an example explaining your point. Like for example, take your first guideline * Once idea per sentence At the end, you could add an example to explain your point.

Wrong way of showing the data. Column order of the data should be Name Company Salary City ..... and so on. Irrelevant details should be towards right end so that people don't have to scroll to see the relevant data.

read papers on ArXiv

Your basic assumption is todo app is not as expensive as the paper in that era. In that era paper was expensive, in this era todo app is expensive which require a smart phone (or a computer or laptop) connected to the internet.