I applaud the effort and share the sentiment that typography is important for the web, but there seems to be quite a bit of problematic advice given.
E.g.,
1) the author suggests a range of 120-150% of leading; the upwards bounds of this is far too much (too much leading causes the eye to skip down a line). Bringhurst's suggestion is much lower---around 12/14pt (Bringhurst is referencing print, not online, so an argument could be made for slightly more leading, but not 150%).
2) The discussion of kerning doesn't mention kerning tables that are built into the font: one doesn't manually kern body text.
3) Tracking, aka, "letterspacing". There's some debate about it, but one doesn't typically letterspace lowercase (body) text (the exception may be very small text). F. Goudy may have said that "anyone who letterspaces lowercase would shag sheep" http://practicaltypography.com/letterspacing.html
While this article is a bit of a mess in many ways (structure, content, design), and I wouldn't take it seriously as a guide to design, you can use leading to give emphasis to things like an intro paragraph or pull quote, in which case 150% is totally fine and you might even go over that. They should probably have mentioned the context in which their advice might have been used, and given examples of different usage. 150% on main copy would usually be way too much of course. Even for main text, personally I find 12/14 to be pretty tight - Indesign for example chooses 12/14.4 as a default, and how tight it feels depends on a lot of factors (face, line-length, weight, density of text (is it head, pull-quote, long body?)). There's a lot of variables there and I'd be careful about making sweeping statements about leading.
I agree the kerning examples are pretty absurd, if anything automatic kerning usually gives you too much space - I've never seen automatic kerning make such a mess of spacing as in their example, and as you say it's something you'd only do manually on heads (and even then rarely in web typography as the tools just are not there to do it well, unless you want to litter your code with manual spans).
The practical typography link you gave is great - that's a much better resource for online typography, and beautifully done:
> 150% on main copy would usually be way too much of course.
I think this is true in general, but fonts that are typically used in web design tend to have pretty tall x-heights (designed that way to compensate for low monitor pixel density). As the x-height goes up, I find the leading can too.
I like the rule of thumb that the line spacing (i.e. distance between baselines of successive lines) should be about 3x the x-height.
But I also do tend to like my lines a bit more spaced out than most. Some sort of weird compensation for suffering through years of painful single-spaced Word documents and old web pages.
It's difficult to make generalisations about line spacing, because so much depends on the typeface you're using. On the web, we normally specify a line-height relative to the font's size, but factors like x-height (or, if you prefer, how prominent ascenders and descenders are) and the line length are also important.
As for tracking, not letterspacing lowercase is a reasonable rule of thumb, but a lot of rules need to be bent when you're setting small text. A lot of the same arguments for bending the rules also make sense if you're displaying text on low resolution media like computer screens (less so on modern high-dpi technologies like Apple's Retina products) and sometimes also if you're setting inverted text (light against a dark background). As always, you have to take the whole picture into account and adjust your typography to your content and your medium.
The comedy 1.5 line gap between paragraphs was what defeated me. I was distracted by the sound of Tschichold turning in his grave.
1. "too much leading causes the eye to skip down a line" usually considered to be the opposite. Small leading causes skips. Which is why many copy editors prefer to work with texts at 200% line-height.
3. Goudy was talking about blackletter. But that is sheep-shaggingly bad for the same reason as lowercase, so it fits, I think. Tschichold (again) said that, conversely, nothing should be set in all caps or small caps without at least a little letterspacing.
Thanks. With due respect, what level of expertise is this advice coming from? (It's also not clear what expertise the author of the Pressla article has.)
The link he gives there isn't his own site, it's an online typography ebook by Matthew Butterick, a professional typographer. I expect most of the knowledge in his comment comes from there as well.
1) the author suggests a range of 120-150% of leading; the upwards bounds of this is far too much (too much leading causes the eye to skip down a line). Bringhurst's suggestion is much lower---around 12/14pt (Bringhurst is referencing print, not online, so an argument could be made for slightly more leading, but not 150%).
2) The discussion of kerning doesn't mention kerning tables that are built into the font: one doesn't manually kern body text.
3) Tracking, aka, "letterspacing". There's some debate about it, but one doesn't typically letterspace lowercase (body) text (the exception may be very small text). F. Goudy may have said that "anyone who letterspaces lowercase would shag sheep" http://practicaltypography.com/letterspacing.html