It works fine on all the other boards I read. That is to say - it takes me to the first post I haven’t read. On the dope, it transports me to a seemingly random post, often before one of my own posts, or pages beyond what I’ve read.
I searched but the most recent threads I found about this were from 2005 - a time when I wasn’t reading other boards and have no comparison for. Also, I figure the software has been updated since then.
It’s one of the primary ways to retain mystery on the board.
I never use the feature myself, 'cause it doesn’t ever work. (Or if it is working, doesn’t perform a feat I desire).
I was just wondering if this was in any way related to the “Last Post” column on the main page. I always find that if I select interesting links from there, whether I’ve read them before or not, that I end up at a random post on a random page of the thread, and I have to go back to the OP to start reading it properly.
Are you using more than one computer? Are you sometimes reading without being logged in? The only time I end up elsewhere than at “first unread” is sometimes at work, when I close the window without logging out, then reopen the window – it won’t reflect what I had read between first opening that page and closing the window.
Where is this feature or button? I have never seen it.
Read the mouse-over on the thread link when you’re at the home SDMB page
Neither.
See, if I click it right now it takes me to #6. It should know I’ve at least read to #7 since I’m the one who posted it!
Edited to add: still takes me to 6.
Oh, I never noticed that.
It always takes me to the last post.
I find it takes me to the first post made since the last time I finished using the SDMB, which may be several posts after I finished reading that particular thread, particularly if it’s on the sub-board I read first. If I go back to a sub-board (e.g. GQ) and look it over again within the same session of board-using, it still takes me to the first post made after the last time I looked at the SDMB as a whole, from yesterday.
Only time it seems to act up for me is when there is more than one page to a thread. The “first unread” then is always the top of the page I haven’t seen, rather than the next post on the page I have read. (This does make sense, but it still brings on a long sigh.) Aside from that – it works well, because it recalls what was the last post number when I was previously viewing. I think. 
How many of those other boards use vBulletin Version 3.0.7? (see bottom of page)
I never have a problem with it.
I looked and they don’t say. If you’d like I can PM you the urls. Maybe you can tell by looking.
I was just curious - a habit of mine when dealing with software issues. The first question is always “what version are you running?” But I’m not curious enough to go look at the other boards and try to figure out what versions of vBulletin they are running.
The only way it could take you to the last post you read is if it keeps track of where your scroll of the page is and knows how big your screen display is. I don’t think vB does that. I always assumed it took me to the first post after the ones in the display I last downloaded.
Example: A thread has 10 posts. I downloaded all 10, but didn’t scroll down to read past #5. The next time I access that thread thru the “first unread” button, I would expect to be taken to post #11 (if there was one). If the software was smarter, it should take you to post #6.
It’s simpler than that. As I understand it, it just takes you to the first post with a post time more recent than your “last visited” time.
Right now, my welcome info sez:
So, when I open a thread with new posts and click on “View First Unread,” it will take me to the first post in the thread with a post time after 3:01 PM.
EDIT: Or, as I just proved to myself, it will take me to my own post if I just posted to this thread.
You’re right. In the example in the OP I was assuming I read all the posts in the thread last time I opened it. Clumsy wording, though.
ETA: Still, it doesn’t work like that for me on the SDMB. I can’t find any consistent logic for which post it takes me to.
Last visited what? The thread? SDMB? A page of a thread?
I don’t have access to the vB source code, but I can’t imagine a comparision between a “last visited” date/time and the thread post. What if you didn’t look at that page, or even that thread during your last visit? Much better to assume that if you downloaded Page N, you might have read it to the bitter end, to Post P. Not a reliable assumption, but better than comparing time stamps.