Depends on the board, some like gambling are almost exclusively spam, some are decent.
If you have trouble filtering decent posts, DannyHamilton made a list that blocks sig spammers.
https://bitcointalk.org/index.php?topic=973843.0Basically anyone with that is in or has been in a signature campaign is there (mine included).
You can create your own list too I suppose.
Wow, that's impressive! Thanks for that. I'll hold off for now as I'm still finding out whose posts I want to see, but I've bookmarked that thread in case I need it later

I see... so the key indicator is when their activity matches their post count? I noticed that happens sometimes and took a moment to figure out how it was possible, but at the time I put it down to coincidence. I know what to look for now, thanks!