My JavaScript screencast, letscodejavascript.com, made over $10K net profit per month at its peak. It costs $25/month for unlimited access to over 600 videos.
I stopped producing videos in April 2018, but the site is still up, and still gets occasional new subscribers. (There's been an influx lately, in fact, and I have no idea why. Maybe because I have a new book out.) It's still netting more than $500/month, although not by a lot. But it requires nearly zero effort from me, so I'm happy with it.
Edit: To clarify, it wasn't a side project when I was producing the videos. But now it's passive income.
Do people ask for support? What I mean is like "x package isn't working" or "I'm having trouble setting this up on my machine", do you help them troubleshoot? Or is it just the videos.
Each video has a comments section, and some of the early videos did get the types of comments you're talking about. I put the answer on the comment page and (in some cases) updated the videos. But I updated the README in the repo and improved the videos, and it stopped being an issue pretty early on.
Now all I get in support requests is the occasional account management email, and those are pretty streamlined at this point. (I could eliminate nearly all of them by creating a proper account management page, rather than directing people to email me, but given the number of requests I get, the cost of doing that is way higher than just handling it by email.)
It helps that the screencast is aimed at more advanced developers. But that's also why it didn't end up being viable in the long term, I think. That and the "long play" format, I suspect.
I'd really would like to know how do you go from video idea to a finished video, especially audio part. I tried making tutorials and just ended mumbling 70% correct facts and rest wasn't actually correct.
The main channel was the “Recorded Live” series, which was basically livecoding with me thinking out loud. That didn’t require any real prep, as I had enough experience with a previous livecoding show that it came out pretty well. The main thing I did was edit out pauses and gaps while I was thinking so that it flowed nicely. I would also announce a pause when I needed to go research something (which was fairly common) and edit a “fade to black” into the video.
The “Lessons Learned” channel was more elaborate. The video at objectplayground.com [1] is my most popular example. For those, I would make slides and animations in Keynote, then record while playing the slides. I had an outline, but not a script, as I felt that made the narration less stilted. Sometimes that resulted in minor mistakes going into the video. For more serious ones, I would record a new line and edit it into the video.
In all cases, I would edit out pauses, and if I misspoke or stumbled over my words, I’d just repeat myself and edit out the mistake. I got pretty good at editing—because there was no video of my face, I could make cuts that were basically invisible. My livecoding videos each had hundreds of cuts, typically just half a second or so. It would take a 20 minute recording down to a 15 minute final video. It took about 4 minutes of editing per minute of final video.
[1] The video on objectplayground.com isn’t showing up on my phone for some reason. You can find it here instead:
It happened very gradually over the course of the show’s 6-year run. (Started 2012, last video 2018.) As for why, I’m not entirely sure, but I think that part of it was that people are more interested in tutorial videos about the latest tools, and my show was almost exactly the opposite: it was about design, creating maintainable code, and avoiding fads. So as the initial audience dropped off, I didn’t have the word of mouth marketing juice to attract replacements.
I stopped producing videos in April 2018, but the site is still up, and still gets occasional new subscribers. (There's been an influx lately, in fact, and I have no idea why. Maybe because I have a new book out.) It's still netting more than $500/month, although not by a lot. But it requires nearly zero effort from me, so I'm happy with it.
Edit: To clarify, it wasn't a side project when I was producing the videos. But now it's passive income.