I'm gonna ask a dumb question

But how do you reply to specific posts on the imgboards?  You know, make it reference back to a particular post?

>>8
I need to know this too.  So I'm gonna use this opportunity to work it out.

[spoilers]Is it this?[/spoilers]

Or maybe this?

<spoilers>This perhaps?<spoilers>

<spoiler>Or there's a tiny chance it's this...</spoiler>