How about altering how the Markdown would be rendered?
E.g., the previously mentioned input:
[Check this cool similar new app out HN](http:/not.suspicious.com/nor/has/tracking)
Could be rendered as:
<a class="link-display" href="http:/not.suspicious.com/nor/has/tracking">Check this cool similar new app out HN</a>
<span class="link-content">[not.suspicious.com]</span>
.link-display {
/* Whatever styling you want for the link itself. */
font-weight: bold;
}
.link-content {
/* A more in-your-face helper that shows at least the domain. */
font-style: italic;
opacity: 0.5;
}
<a class="link-display" data-host="not.suspicious.com" href="http://not.suspicious.com/nor/has/tracking">Check this cool similar new app out HN</a>
.link-display:after {
content: " [" attr(data-host) "]";
}
E.g., the previously mentioned input:
Could be rendered as: Example: https://jsfiddle.net/upb7o0zm/