Meaning of symbols next to thread titles and title bolding.

I searched the FAQs, didn’t find the answer, so I’m bringing it here.

In each forum, to the left of each thread, is a little symbol. I’ve seen an envelope, a corkboard with a sheet of paper on it, and a corkboard with two sheets on it. What do these symbols mean? Also, why are some thread titles highlighted while others are not? I figured the non-boldened ones were older, but I’ve seen new threads or threads with recent posts that are not boldened. Why?

A minor thing, but its bugging me.

Look at the bottom of the forum pages. There are legends there that explain them. The corkboards are for subforums and you see them in Main, while the envelopes are for individual topics.

Bold topic title means the topic has new posts (or it’s a new topic) since whenever the board deems your last look at the board to have been. It’s not completely accurate, but it’s close enough.

Cool. Thanks.