I'm increasingly seeing a lot of technical and business writing make heavy use of bold font weights, in an attempt to emphasize what the writers think is important. LLMs seem to have picked up and spread this practice widely. But most of this is self-defeating, the more a writer uses typographical emphasis, the less power it has, quickly reaching the point where it loses all its benefits.

There are various typographical tools that are used to emphasize words and phrases, such as: bold, italic, capitals, and underlines. I find that bold is the one that's getting most of the over-use. Using a lot of capitals is rightly reviled as shouting, and when we see it used widely, it raises our doubts on the quality of the underlying thinking. Underlines have become the signal for hyperlinks, so I rarely see this for emphasis any more. Both capitals and underlines have also been seen as rather cheap forms of highlight, since we could do them with typewriters and handwriting, while bold and italics were only possible after the rise of word-processors. (Although I realize most of my readers are too young to remember when word-processors were novel.)

Italics are the subtler form of emphasis. When I use them in a paragraph, they don't leap out to the eye. This allows me to use them in long flows of text when I want to set it apart, and when I use it to emphasize a phrase it only makes its presence felt when I'm fully reading the text. For this reason, I prefer to use italics for emphasis, but I only use it rarely, suggesting it's really important to put stress on the word should I be speaking the paragraph (and I always try to write in the way that I speak).

The greatest value of bold is that draws the eye to the bold text even if the reader isn't reading, but glancing over the page. This is an important property, but one that only works if it's used sparingly. Headings are often done in bold, because the it's important to help the reader navigate a longer document by skimming and looking for headings to find the section I want to read.

I rarely use bold within a prose paragraph, because of my desire to be parsimonious with bold. One use I do like is to highlight unfamiliar words at the point where I explain them. I got this idea from Giarratano and Riley. I noticed that when the unfamiliar term reappeared, I was often unsure what it meant, but glancing back and finding the bold quickly reminded me. The trick here is to place the bold at point of explanation, which is often, but not always, at its first use. 1

1: For example, sometimes a new term will appear first in a list. Eg “We carry out this process in three steps: frobning, gibbling, and eorchisting”. In this case we don't bold the words as they appear in the list but later on when we explain what on earth they mean.

A common idea is to take an important sentence and bold that, so it leaps out while skimming the article. That can be worthwhile, but as ever with this kind of emphasis, its effectiveness is inversely proportional to how often it's used. It's also usually not the best tool for the job. Callouts usually work better. They do a superior job of drawing the eye, and furthermore they don't need to use the same words as in the prose text. This allows me to word the callout better than it could be if it also had to fit in the flow of the prose.

A marginal case is where I see bold used in first clause of each item in a bulleted list. In some ways this is acting like a heading for the text in the list. But we don't need a heading for every paragraph, and the presence of the bullets does enough to draw the eye to the items. And bullet-lists are over used too - I always try to write such things as a prose paragraph instead, as prose flows much better than bullets and is thus more pleasant to read. It's important to write in such a way to make it an enjoyable experience for the reader - even, indeed especially, when I'm also trying to explain things for them.

While writing this, I was tempted to illustrate my point by using excessive bold in a paragraph, showing the problem and hopefully demonstrating why lots of bold loses the power to emphasize and attract the skimming eye. But I also wanted to explain my position clearly, and I felt that illustrating the problem would thus undermine my attempt. So I've confined the example to a final flourish. (And, yes, I have seen text with as much bold as this.)