LinkedIn cuts your post at around 210 characters and drops in a "see more". What stays visible is three lines on a desktop, often two on a phone. The rest only exists if those lines did their job.
It is a purely mechanical constraint, and it explains a good deal of what irritates you about your feed. The blunt openings, the sentences cut mid-thought, the beginnings that promise without saying anything: those are not authorial tics, they are answers to a truncation.
What the reader actually sees
The threshold moves with device, language and layout, but the order of magnitude holds: roughly 210 characters, line breaks included. An empty line therefore costs as much as a short sentence, the detail most people miss.
In practice, a post that opens with a hook, an empty line, then a second sentence has already spent half its visible space on white. Sometimes that is exactly the intent. More often it is an accident.
"Five years ago, I walked away from everything. The salary. The title. The comfort."
Here, everything visible before the click fits in the first sentence. The rest is held on the other side of the "see more". The device is effective, and perfectly legible once you know what you are looking at.
Four ways to spend the space
There is no single good opening, there are a few that work for different reasons. These are the ones you meet most, from commonest to rarest.
The gap between the hook and what follows
This is where almost everything is decided, and nobody talks about it. A strong hook creates an expectation; if what follows does not meet it, the reader does not merely leave: they remember you as someone who made them click for nothing.
The pattern-break hook suffers exactly from this. It still works, but its yield is falling because too many posts used it with nothing behind. The technique is not worn out in itself: the trust is.
The panel shows a hook score built from the length of the first line and what it promises. It also tells you whether the useful information arrives before or after the cut.
A two-minute exercise
Take your last three posts, cut them at 210 characters, and read what is left as though you did not know the rest. Would you click?
Most of the time the answer is no, for a simple reason: you write your opening while thinking about what comes next, whereas the reader does not have it yet. Writing the first three lines last solves a good part of the problem.