This may simply result from minor international differences in the use of English, but thought I’d throw this out anyway.
On the front (index) page of the forums, down near the bottom-right there’s a button (or link, I forget which) “Mark all messages read”. Typically (and I’m sure many others here do the same) I’ll click that when I’ve looked at forums and postings I’m interested in and am about to leave the site, so ones I’ve skipped aren’t still flagged as unread on my next visit.
Since I think of “messages” as PM’s and the like, or system messages, would it make sense to change the wording of this button (link?) to “Mark all postings read” or something similar? Many mail clients also use “messages” to refer to individual emails, and I run into the same minor confusion there.
Over at Wilders (and several other boards I frequent), the equivalent is labeled “Mark forums read”. Of course, that might be “hard-wired” into whatever board software a given site uses.