The phrase should be used to indicate that what I have just read is incomplete. That by clicking the link, additional information will be revealed.
Instead, in a handful of recent cases I have clicked on it to get to the exact same information. There was no “more” just the same. They probably meant: read the original version.
The few causing me frustration appeared on blog sites who just repost other stuff. Maybe their tools were designed to reshare an excerpt instead of all 6,000 words? Incorrect use of them is why they indicate the wrong thing.