I found this while perusing a Ranker site. 
Where have you unexpectedly come across a SD reference?
Can’t remember the exact topic, but I know I’ve seen Wikipedia cite the Dope.
Which is interesting because the Doper might have been citing Wikipedia.
We were cited in Randall Munroe’s (of XKCD fame) book IIRC. It was this one.
I’m not quickly finding it, but a post from a Breaking Bad thread was quoted in a (print) magazine. I believe it was a fan theory that poster got/copied from an unknown source at reddit.
My personal one and and the most ‘in the wild’ one for me (but not really a ‘reference’). Back when the Online Dating Thread was in full swing and we’d use it for questions, be it general advice or specific questions about a situation, I was about to email a girl for the first time, but had a question about how to handle a certain aspect of it. Literally minutes before I posted my question to the thread I realized that the girl I was going to ask about was not only a Straight Dope member, but also very active in that very thread. That, in and of itself is a good reason to always think about what you say online. Even if people aren’t looking for things about themselves or poking around to see how you act online, as Phil Collins says, ‘you never know who’s looking on’.
Beyond that, we’ve had quite a few members (that we know of) on Jeopardy!.
There’s a few I’ve come across on TV Tropes.
The Reality Check (a Canadian podcast) frequently cites The Straight Dope.
My first encounter with The Straight Dope was when Cecil’s poem about Schrodinger’s cat was reprinted in Physics Today.
I have run across it a few times in general and even been quoted by my user name in a feminist blog no less. One notable example was Scylla’s “The Horror of Blimps” story that went semi-viral before such a concept barely existed, plagiarized all over the web and eventually made it into an actual published book I believe.
Looks like it would be a funner-than-average clickfait link, but it won’t open. Nor will any of the other links on the page.
One I forgot about:
I was at work and told a co-worker something. For one reason or another he refused to believe me and wanted a ‘second opinion’. He pulled out his phone and googled it and said ‘okay, you’re right, says it on the internet’ (which is semi-odd for him. He not only doesn’t just believe what he reads on the internet, but tends to default to everything being wrong and the everyone being trolls, but that’s another story). Anyways, he immediately takes the advice I originally gave him. The advice was medical in nature and based on whether or not he could could take a certain med. So, he takes the pills, then reads me what he read on the internet that convinced him that NOW it was okay, but when I said it, it was wrong. “Hold up there”, I said, “what web site are you looking at” and he replied 'ummm, it says straight dope . com". To which I said “you asshole, that’s MY post, look at the user name”. I knew it was me, I recognized what he said. To this day I still give him shit for not believing what I said, but believing"the internet" even when it’s still me, just me on the internet.
I mean, I get it, he just wanted another opinion, I just think it’s pretty funny that his ‘second opinion’ was also me.
Later on, I realized what happened. When he was using google, he used the same wording/sentence that I used IRL to tell him it was okay, so my post came up since I said the same thing here.
That has happened to me several times as well. What is more embarrassing is when I look some obscure thing up, think the answer is brilliant and then realize that I am the one that wrote it a decade ago.
The SDMB may not be one of the biggest sites on the web but it has been around a (relatively) long time and Google heavily favors it for many obscure topics. That didn’t used to be the case. Back in the old days (early 2000’s), you had to find this site in the first place and use the fairly rudimentary search feature to find anything at all. Now, anyone with a smart phone can find anything you have written in the past 18 years in 2 seconds.
That can be both good and bad. I have had several people contact me and even identify me personally based on older things that I wrote. Most of them were just curious and happy to find information but a couple were really pissed off even though what I said 15 years ago was accurate.
I spotted a Straight Dope book on “Seinfeld” once Straight Dope book seen on "Seinfeld"? - Cafe Society - Straight Dope Message Board