Keeping track of read threads

I did a search and couldn’t find anything on this, but if this has been covered, feel free to just link to those threads.

I find that when I’m logged in, the message board keeps track of which threads I’ve read differently than when I’m just in lurk mode (reading the board not logged in). When in lurk mode, the board keeps track of each thread that I’ve read and whether it’s been modified. When I’m logged in, it seems to be less granular – anything that hasn’t been updated since last time I checked the board shows as read, whether I’ve actually opened the thread or not.

For example, say there are three threads, A, B, and C. I go to the SDMB and look at B. An hour passes (if I can wait that long), and during that time, C has a new post but A and B don’t.

If I revisit the SDMB when logged in, A and B will look like they have no new posts, even though I haven’t looked at A. C will show a new post.

If, instead, I revisit the SDMB when not logged in, A and C will both show that they have new posts since the last time I checked those threads, and B will show that it has been read.

I prefer the second mode, since the SDMB more accurately displays whether I’ve looked into individual threads, but that means that I have to stay logged out most of the time. Is there something I can do to cause the second behavior, even when I stay logged in all the time?

So, I guess no one else sees similar behavior. I use Opera mostly, but I can’t imagine that the browser has anything to do with it.

It’s a bit of a shame for me, really. I’d like to participate in more discussions, but my somewhat obsessive nature makes it tough for me to miss out on things, so having the more granular view of which threads are really read (seemingly only available when I’m NOT logged in) is really helpful.