I have exactly one inbox for reading blogs and following news, and it's expressly not my e-mail client—it's my feed reader. (Looking for a recommendation? Here are some instructions on setting up NetNewsWire; for once, the best app is also the free and open source one.) Anyway, with the rise of Substack and the trend for writers to eschew traditional web publishing in favor of e-mail newsletters, more and more publishers want to tangle their content up in your e-mail. Newsletters work becau...