Does anyone on here run a free/paid newsletter such as on substack or via collected addresses fed into an email service (e.g Mailchimp)? Or if you are just a reader, what do you think of the different platforms/services such as Substack and would you/do you subscribe to email newsletters?

I'm currently in the process of using the relatively new platform called beehiiv to set one up to go alongside my blog website. It's very expensive to go all in on the platform to be able to use a custom domain, monetisation and growth tools (like a referral programme) when building an initial audience ($99 a month!), but I guess the idea is you stick to the free tier until you get a decent amount of subscribers. With a big audience the prices are actually competitive v other mass email services/platforms. While you can do premium subs, they also have an ad network and something called "boosts" where you get paid to promote other peoples newsletters to your audience (then maybe use the credit to boost your own site instead of withdrawing), so you aren't relying just on subs.

Substack has no up front or ongoing direct costs with the model being a 10% cut of premium subs to your newsletter. They don't really have any other provided monetisation options (other than sorting ads out yourself) however their discovery and recommendation tools for readers are very good and you can pick up a lot of subs just from people discovering your content and following/signing up.

Youtubers on here could use newsletters as a way of directly reaching out/keeping hold of your audience (lets say the Youtube algorithm treats you badly in the future) , further monetisation options and a traffic driver to the Youtube channel.