Pretty simple when I take my cursor and hover it over the link at the Forum Page. But once I get to the forum, this shows up in my address bar:
http://boards.straightdope.com/sdmb/forumdisplay.php?forumid=12&daysprune=
The “&daysprune=” is extra, and I’ve never seen it before. Has it always been there? If not, is it due to the prunings? If so, what does pruning have to do with http addresses?
I’m pretty sure it has nothing to do with recent talk of pruning threads. I’d say I’ve always seen it. I think it refers to how many days’ worth of threads a forum displays for you (which shows up as an instruction to the database).
The daysprune refers to the number of days’ posts being displayed. Try loading any one of the forums, then changing the number of days being displayed. The URL will change to reflect this.
You’re absolutely right, mattk. I tried sticking in 10 after the = and sure enough, it displayed the last 10 day’s worth. For some reason, though, that extra bit doesn’t show up on my GQ page, although it’s there for all the others.
Anyway, thanks for the answers!
You can edit your default settings for “number of days worth of threads” on your Profile Page.
And while this is sort of a WAG, I’d like to add the following. If you’re a daily visitor of the SDMB, or if you’re one of those readers who just scans the first page of a forum anyway: don’t set your default too high. Two days is fine, in most cases (hey, it’s what the moderators use [well, this one…]! It can’t be bad!). It would appear to me that setting the standard at “10 days” or even more means that our server has to do an extensive lookup (basically for nothing if you were here yesterday as well) everytime you enter one of the fora. If you’re not using the results of such a lookup anyway, you might as well turn it off, right?
There’s tons of options in the drop-down box, from one day (or forum default, which may be different from forum to forum) to “all threads”. Please think about this a bit and choose something logical for your situation.
If my reasoning here is way off, a more enlightened colleague will be along shortly to slap the living snot out of me. 
In response to my own little question in this here thread, administrator jdavis said the following:
If anyone knows, it should be Jerry, so it looks like your reasoning is A-OK.
Does this mean I’m “more enlightened”?
It means you were at least smart enough to do the search I should have been doing. Of course, I was trying to avoid stressing the server. 
I meant to add this: if you choose anything longer than “forum default” in the aforementioned settings, Jerry’s work will be for nothing, effectively. Especially if you’re one of the “please gimme 45 days worth of threads” crowd.
Well, I hope none of this is directed at me. My defaults are “Last day” and today was the first time in a long time I touched that menu. Heck, I’m so speed-oriented I stopped using my sig, for the most part. Don’t know if it helps or not, but I figure it can’t hurt. Heck, we should get rid of sigs altogether. Has this been considered? And I never do searches during the slow hours.
Good lad!!
Yes, sigs require a look-up whenever you engage them in a post, so they do slow things down. And yes, we’ve discussed getting rid of them altogether. So far, we decided to leave it as it is. But the time may come, who knows.