With regard to newsletters within WordPress, there’s a plugin called MailPoet that (I think) does everything that was talked about in this episode concerning newsletters and storing subscribers in the WordPress database. It might be something with some code you could look at to implement at least some of the pieces.
Since Simple Location got a bit of time in this episode, I’ll take the time to thank you for this plugin, because you actually solved a totally unrelated problem for me. Well, I suppose it’s partly related. I downloaded an app for my phone a couple of years ago called Day One. The idea behind the app is that you can keep a journal and add photos, location data and weather for context to each day’s entry. Only problem is, the app’s interface is mostly inaccessible with VoiceOver, which ultimately makes journaling in this way very hard. But I like being able to add context to journal entries instead of just keeping everything in simple text files. Now that we have Simple Location for WordPress, I can use it, with a combination of private and password-protected posts, to do journaling while adding context. So, huge thanks for all you do, and especially for the Simple Location plugin. Looking forward to the next episode of An Indieweb Podcast.