Not sure what exactly it is you are talking about... event icons? Are you talking about the "stick pin" on the suicide walk post? I think moderators and/or John are the ones that do that according to importance. Dunno... maybe it happens when you start the thread and rate it with as many stars as you can. If not, can't answer your question but it will be interesting to find out what it is or what/who does it and why.
Oh, and I see Doc John has an arrow on his "Bugs" thread. Right below it is one that has fire by it. That's a "hot" thread. I think that appears after so many reponses. Those icons are the ones you're talking about??
__________________
Psalm 119:105 Thy word is a lamp unto my feet, and a light unto my path.