Agree on updating articles over time. Text is infinitely tweakable and there's so many ways to improve it over time (often in response to comments I'll reword things, create/update diagrams, fix typos, etc. -- if there's an issue with a YouTube video, there's not much you can do.)

I wasn't sure about email either, but Patrick's post demanding I do something convinced me:

http://www.kalzumeus.com/2012/05/31/can-i-get-your-email/

(He actually sent an email saying that was the most important thing to do, yelling it, and said 1% of people would actually follow it. I decided to start it just not to fall into the trap.)

Here's what I've found personally:

1) It has a better chance of being seen than other social channels. I don't want to be buried under political news and entertainment on Facebook, twitter, etc. Also, many older folks aren't as familiar with tech, but check their email.

2) It's a self-selected group. Here's a set of people who want to hear from me, which means I can be myself a bit more when writing a newsletter update. I imagine I'm writing to some friends who want to know what's going on. I used my email list to get 50 paid beta customers for my Calculus class, which was itself delivered by email in its first iteration.

3) Marketing is way better. I sold more books by announcing it to my 20k email list (at the time) vs. getting on Reddit and HN homepages, with ~1M pageviews.

4) Engagement is higher. Many people reply to the email and we have a quick (or long) conversation, but they don't want to leave a public blog comment. Also, it helps keep in touch with a larger set of people.

5) For numbers, I have about 38k people, 35% open rate, maybe 5-10% click rate depending on the content. If your audience isn't engaged you should prune/remove people who haven't opened it in a while. But, for an engaged audience, you can get thousands of people to take a look at something.

6) Help people get started. I have a short auto-sequence that goes out with 3 lessons (I'd like to make more). Getting a gentle nudge every week with some new content helps people (vs. having to remember each week to find some articles to read).

When people think of "newsletter" they think of spammy groupon emails designed to sell sell sell. I aim for simple, plain-looking updates (not technically plaintext, sometimes I have images), with a casual vibe. "Hey, have something new you might like. Enjoy."

7) On what I write: announcements of new articles, new product launches, requests for beta customers. I probably email 1-2 times per month on average.

8) Lastly, it's fun for me. I don't like the FB/twitter environment that much -- it feels too much like a stage -- with email, I feel like I'm chatting with friends around a table.

The impact of evergreen content was my biggest eye-opener. The more time, the better, but don't beat yourself up about "lost time". Just start today. Before we know it, 2, 5, 10 years will have passed.

This worked for blog posts, starting an email newsletter, selling books on Amazon, making YouTube videos (for standard math concepts), design improvements to the site, etc. You plant the seed once and it bears fruit for years.

The newsletter is fully optional, basically to get alerted to new articles & other site news. The homepage should be fully scrollable with a big list of articles, you can also check out:

https://betterexplained.com/cheatsheet/

for a visual guide. That said, I'll definitely think about rewording things, and I've long wanted to make a "Getting started" section for students, teachers, parents, etc. Really appreciate the feedback!

That discussion was an eye opener for me (in a good way), it showed me of how easily things get muddled in online discussions as context goes missing. It always reminds me to really see what the other person is thinking.

On paper it reached "success" (sold for millions, is now a Top 500 site) but unfortunately it's far away from its original mission.

There's been countless studies about happiness and income, but I realize once my reasonable needs are met, my life satisfaction comes from things that can't be bought (getting in the zone, helping people, feeding my curiosity).