From 2017 until 2023, I was an editor for a blog site that got 2 million unique visitors a month. Whether I liked it or not, I had to learn something about the "ideal" blog post. As with all media, blogging is received in a specific way by most of its audience. People tend to read blogs differently than how they read a book or a comic or an RPG rulebook or a tech manual or anything that's not a blog. Whether you like that tendency or not, it's important to understand what your audience implicitly wants from you. What people want is a short article. I'll prove it to you.
With few exceptions, blogs are perceived as non-fiction. When you read non-fiction, you basically expect the scientific process. You want the author to make a claim, to prove it to you, and then let you get on with your day.
You do NOT want the author to make a lot of unrelated claims or to get distracted from the point.
When you write a blog post, have a single point in mind. Write your post to support that point. You don't need to convince your reader or to excuse yourself for your thoughts. If a reader doesn't like what they're reading, they'll stop reading with or without your permission. Just make your point, and end the post.
Vertical scrolling is a classic measurement used in search engine optimization (SEO). Using server logs (and analytical services like Hotjar), professional marketing people look at "heatmaps" of pages to determine when visitors click away from their sites. They base this on how far down a webpage each visitor gets before leaving.
For that reason, some web publishers determine article length by lines of text rather than by word count (the traditional publishing metric). For that to work, you have to write every sentence on a new line, with a blank line between paragraphs. That might sound awkward, but actually if you're writing in HTML or Markdown (both of which are common formats for web publishing), it's easy to do because HTML ignores line breaks and respects only paragraph tags. In other words, the source code of your article has a line count, even though readers see it in traditional paragraph form.
Generally, 100 lines is a good length for a blog post. It's enough time for the writer to make one single point, and it's a comfortable amount of time for a reader to spend in one place on the very very busy modern Internet.
You probably think your blog post can't be reduced to just a single point. And you're probably right. Assuming you have a series of related points, and you want people to read about those points you want to make, then you have a serial. When you catch yourself writing a blog post that's actually more than one blog post, split your article into several different posts. You'll recognise a post that's too long when you notice that you have two thesis statements in one article, or else you're writing more than 100 lines of text in one file. The Internet has hyperlinks for a reason. String a bunch of blog posts together, and let the reader decide whether your first point was made well enough for them to continue on to your next point.
I'm not a huge fan of search engines or of search engine optimization. But you don't have to chase after numbers to make your writing easy to read. There are lots of reasons people don't read long blog posts, and none of those reasons have anything to do with you or me personally. The way we use the Internet is different from how we use paper magazines, paperback books, hardcovers, ebooks, and so on. So if you're going to write, write for your reader, whether it's that one reader who comments on every post, or those 3000 readers who subscribe to your funding platform.
I said at the start of this post that I'd "prove" that short articles are better than long ones. If you're reading this paragraph, then you've experienced a 56-line blog post that has made a single point and then ended. You scrolled down this far, and you probably read at least the first sentence in each paragraph, which is all any writer can ever hope for. But admit it, if I'd gone on for 256 lines, you'd never have seen this paragraph.