Question: Is there a [leading](https://en.wikipedia.org/wiki/Leading) (i.e., *line spacing*) commonly considered appropriate for most types of blogs? I'm referring, specifically, to "regular" blog posts, i.e. not asides, snippets, galleries, etc.¹

For my purposes, you could define this as a minimum of 500 words.

Please note that I'm not talking about a "standard" leading (although if, by some miracle, it exists, please do tell), but merely one that is *commonly agreed upon* or, at the **very** least, commonly *used*. (Basically, I'll take whatever you can give me; I just want to get *as close as possible* to a standard as one can observe in blog writing.)

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¹ On WordPress.com, these would be labeled *Text* posts, the others often being *Photo*, *Video*, *Quote*, *Link*, *Aside*, *Gallery*, *Status*, *Audio*, and *Chat* posts. ([See here.](https://en.support.wordpress.com/posts/post-formats/))

Answer: 
Although with respect to the post by "what", I must disagree that leading is defined by the user. Most users have very little knowledge of adjusting their browsers anything beyond default.

This leaves the decision of leading to the blog writer, who may or may not be skilled in CSS to be able to alter it.

As such, standard typography conventions for leading usually default to 120% of the point size of the type. Thus a 10 point font usually gets 12 point leading. However, the most finely typeset documents, are ones that have been manually leaded and kerned (another discussion). Meaning, depending on the specific font, the leading is adjusted manually for optimum reading.

Also a consideration from the print world, is the length of the line of text. In print, a line of text should average 9 - 15 words, much like how the lines are being displayed here.Lines with much longer text will require more leading, whereas shorter lines will require reduced leading.

Summary: dependent on font. Investigate CSS.
The "appropriate" leading on websites is that defined by the user agent.

Unfortunately a large number of web designers appear to be unaware of the fact that users use a wide variety of operating systems, screen sizes and web browsers. The best usability experience is that provided by user agent standard settings.

Unless you are very sure what you do (and how to do it correctly), do not change font size, line height and other font metrics on a website.