Apparently I lurked almost half a year before asking the magical question:
How I missed the “need answer fast!” aspect I’ll never know.
What was yours?
I actually still remembered what it was!
I have no idea. The software won’t give me posts that far back. The last 500 of mine only gets me back to the middle of the year.
I really need to get a life.
I can’t go back that far either. I think it was a question about why some gas stations take those little latches off of their gas pump handles so that you have to hold the handle the entire time. It turns out they are called latch open devices they are against the law in some states like mine but not others and is considered to be a safety feature in case the pump does not shut off automatically. I still have never heard of a problem with one.
I think my first post was in a Jean Auel book discussion thread, about how I was glad that someone else found her extreme overuse of comma splices annoying.
And that, after* six* or more years of lurking on this board and not registering. 
SDMB search is useless for this kind of thing, but you can search via Google using a date range.
http://boards.straightdope.com/sdmb/showpost.php?p=3516811&postcount=52
Earliest I could find for you, but I quite like it!
(Can you tell I’m bored and sick in a hotel room? Well I am.)
April 18th, 2000. Time is of the essence! What essence?
I think that’s my first post. I’d lurked for about half a year before registering (and hence missed out on being a 99er), but once registered I think I posted pretty quick.
Pretty sure mine was in The Pit, which is weird since I rarely even go there. A guy with chronic pain was posting and I posted some suggestions about coping with pain. I didn’t plan to ever post again, so I didn’t bother to come up with a cool name.
Do an advanced search on your username, results as posts, set it to 10 years or newer, in ascending order. It should work.
Yeah, I never would have used my real name as my username if I 'd known I’d be posting here so much and so long.
Looks like this is my first post. I had lurked for sometime, but I guess I finally decided to sign in and post this:
http://boards.straightdope.com/sdmb/showpost.php?p=4842744&postcount=27
Thanks! I guess that was it. It is like a time-capsule and basically the way I remembered it.
I was always a smartass, but in my first post, I was apparently a funny smartass. Then I lurked for another couple of years.
Mine was 11/25/2001:
It was a thread speculating about what had happened to posters who hadn’t posted in quite a while. Some of the events speculated to be delaying or preventing them were convoluted and painful sounding.
Mine is here… http://boards.straightdope.com/sdmb/showthread.php?p=8233762#post8233762
Wow, I’ve been here almost 6 years now.
Don’t know for sure. I know I started a stupid thread that was actually a joke and got a caution from a mod for it. I responded with something inadvisable like “oohh, I’m really scared.” In my defense, I was totally unfamiliar with message boards and the rules thereon back then. Hard to believe, I know.
Alternately, I find this thread in which you mock Brits but are not warned (or should I say cautioned)?