I believe that users should have the ability to highlight posts within a thread that they created. The main use for this would be to add updates in #rwa stories or for virtual airlines to announce changes within their VA. This would allow for users to scroll quickly through pages and catch up with the latest.
This isn’t something we can do anything about as Discourse does not allow users to highlight posts unless they are staff. Not without some custom plugin anyway.
Well darn it…
Sorry about that.
As @PlanesAndGames mentioned you can use
<mark>test</mark> = test
Not other people’s posts…
Unfortunately this feature is not available to TL3 and below. Should Discourse allow it in the future, we will consider it