Here’s a terrible idea for any social networks with a boost feature: for any post with an external link, intercept any requests going to the site, and inject some tracking into the destination page that will monitor how long the user is on the site plus the position of the scroll bar. What you’re interested in knowing is that they’re reading the article, as best as you can determine that through heuristics such as average reading time, and whether they’re moving the scroll bar. Then, when they go back to boost the original social media post with the link, indicate in some way that they’ve actually read the linked article.
As nice as it would be to have a way of boosting a link with a clear indication that you’ve read it, this approach will not be fool proof and no one wants tracking injected into their sites. So don’t actually do this. 😜