That's red, I think.

If you mean orange:

> Additionally, founders of YC companies see each other's usernames show up in orange, which--although not an explicit benefit--does allow fellow YC founders to immediately identify one another in discussions.

Submitters' names aren't highlighted in any way.

Thought I was going crazy for a bit, but submitters names do show up in red for me. Possibly an extra feature of the Hacker News Enhancement Suite :). TIL.