The Bold Text Trick Behind Eye-Catching LinkedIn Posts
LinkedIn's post editor has no bold button, and yet bold text appears in posts constantly. The trick is that those are not bold letters at all. The LinkedIn Post Formatter converts plain text into them.
They are different characters, not formatting
Unicode contains whole alphabets of mathematical letters - bold, italic, bold italic, script, double-struck - intended for mathematical notation, where a bold capital and a plain capital mean different things.
So the bold-looking letters in a LinkedIn post are those mathematical characters, substituted one for one. The platform is not formatting anything; it is displaying the characters it was given. Which is why the effect works in any text field anywhere, including places that clearly never intended it.
The costs, which are real
Screen readers. This is the serious one. A screen reader encountering mathematical bold letters may read them character by character, read them as "mathematical bold capital A", or skip them entirely. A post written in them is somewhere between unpleasant and unreadable for anyone using one - and on a professional network, saying your headline is inaccessible to blind colleagues is not a small thing.
Search. The characters are not the letters they resemble, so a search for a word spelled in them does not match. A heading in fake bold is invisible to search.
Copying. Paste it elsewhere and you get the odd characters, not bold text, which can arrive as boxes.
Rendering. Older systems and some fonts show tofu boxes instead.
Using it without doing damage
The honest position is that it is a legitimate tool used sparingly and a problem used liberally. A few words emphasised is a reasonable trade. A whole first line, a headline, or every subheading is not, because that is exactly the text a screen reader user most needs.
Never use it for your name, your job title or anything someone might search for. Never use it for a whole post.
The alternatives are better than people assume: a short line on its own, a line break before a key point, or simply writing the important thing first. Structure draws the eye as well as weight does, and it costs nothing.
Common questions
Does LinkedIn penalise it?
There is no evidence of a ranking penalty. The costs are to readers, not to reach.
Does it work in a headline or a bio?
It does, which is precisely where it causes the most harm - those fields are read aloud and searched more than posts are.
What about italics and other styles?
Same mechanism, same trade-offs. Script and double-struck are worse, being further from the real letters.
Can I use emoji for emphasis instead?
A single one as a marker is fine. The Emoji Picker finds one quickly, and a row of them has its own readability cost.
Why do some posts show boxes instead of letters?
Because the reader's device has no glyph for those characters. It is the same failure as a missing emoji, and it makes a post look broken rather than bold.
Want to convert a line of text?