This is awesome. Nice and approachable - well explained. I'd love if you also threw in some vim commands along the way.
An unobtrusive way to introduce editor tips that just came to mind would be to add subtitles with selected key-combos that might be nontrivial or not obvious. More than that would be a distraction, I think. Also, I don't know if YouTube supports multiple subtitle tracks... so that might be a big fu to deaf or hearing impaired programmers who want to follow along.
No, I wouldn't want them to casually say anything... that's why the subtitles would be an unobtrusive compromise, since you can just turn them off. I think this would be even more important if the screencast was targeted at new users of the language or framework or whatever, since the viewer might be confused and wonder if ":tab" was something to do with the syntax of the language.
Really nice video, looking forward to more!
My biggest focus in using vim was to get it out of the way so that I could focus on the Haskell. I wanted the environment (editor, compiler, window manager, test runner, etc) to be as transparent as possible. This is not, in point of fact, a series of vim tutorial videos.
I will make a video that explains my dev environment as a supplement, however.
I'd be happy to answer any vim questions in the comments (github issues, which I will hopefully figure out how to embed in the site eventually), and I do like the idea of adding call out boxes (no need to use subtitles, they can go on the video itself) to highlight interesting vim trickery.