One or two spaces after a period? How about three?

[MBCook]

I’d always heard it was to try to minimize rivers in text. I don’t see that mentioned.

https://en.m.wikipedia.org/wiki/River_(typography)

[James_Henry]

Check this out: http://widespacer.blogspot.com/2012/12/a-river-runs-through-...

[James_Henry]

They don't mention it here, but I think they might on a different post? Rivers are going to show up more in a monospace font (which your link points out), so that would make sense. With modern fonts it makes sense to be putting the spaces in after a sentence stops for readability though. Microsoft word allows for manipulating spacing anywhere there are still rivers.

[James_Henry]

I've always been annoyed by the way html treats whitespace. Having more space between sentences is so much more readable.