The explanation on that page makes sense: "Regularly use the link which marks individual sections or the entire forum as read" to reduce this logging. Without this, I couldn't use the (very convenient) new button to jump to the latest unread posts.
However, logging which topics were read doesn't mean I've seen all posts. I don't think the forum stores which pages of the Wall Observer I've seen.
I'm not entirely sure, I've never really taken enough notice on how the unread posts work, and can't verify it right now due to recently marking all posts as read. I'll keep an eye out in the following days. Since, the forum has to keep track of unread posts somehow, I'm wondering to what extent does it log to keep track of that. Whether, it's done page by page or not.
Isn't this just normal web server behaviour?
Possibly, obviously the information on that page is rather vague. Doesn't really say exactly what's being recorded to the database, and what isn't. I imagine the forum hasn't been altered too much from the original Simple Machines in this regard. Obviously, it has been heavily modified, but I'm not sure if theymos would've made changes to this specific behaviour compared to the default, so we could potentially take a look at how SMF does it by default. Whether, it records each individuals access to each page.
However, the other entry is obviously easy to identify what sort of information is stored, which is pretty standard on most forums.
Imagine that this information was recorded in a txt file. Each topic had to have a file. And each time a user enters the topic, his name is registered in the file.
We have topics with more than 100,000 views, which would require that text file to have 100,000 lines, each with the name of a user.
That made that file occupy 1 or 2 MB. If we multiply that by 100,000 topics, we're talking about 100 GB of information, just to say which users visited a topic.
This suggests it does:
Log of all viewed topics
This pretty much confirms it:
Regularly use the link which marks individual sections or the entire forum as read. This deletes all past individual-topic logs on the marked-read boards. Or view sensitive topics only while logged off.
From my interpretation (especially the part I've made bold within the quote), the second quote confirms that it keeps track of each user viewing a thread, since it suggests you can kind of obfuscate this via marking all existing threads as read. So, while it doesn't record in to a text file in the example you've given, it does record each thread a user has visited. The forum isn't doing anything with that, and you're quite right if you were too display who has visited a thread along the lines of what the OP was suggesting, it would quickly rack up the storage required since you'd need to store it for a lot longer than the forum current does. Since, the logging that is done currently, gets cleared after a while, so it's not a big deal:
Until deleted + about 6 months
