This is the closest I've heard to one of the ideas that we expected to work, so I'll share.

- Create an ad on Facebook with her picture.

- Target people that went to her high school within 4 years of the range of years we thought she graduated within. Was only a few hundred people so the cost of running the ad would likely only be a few bucks.

- The ad copy / landing page just needed to be convincing that we weren't stalking her. We went with the "help us win a bet" approach but the "lost camera" approach would have been good also.

Ultimately we got the answer sooner from another approach after we found out that we had another picture of the girl that Justin didn't know we had. So we canceled the ad, but I think this would have worked if given enough time.

Proof that your friends are your biggest privacy leak. People will tell just anything to anyone.

They didn't actually try it, so there's no proof.

Actually, they tried it... but stopped it before it ran its course.

You had another picture that showed where she worked? Used LinkedIn and company's webpage (Some company list their employee) to narrow it down to a few people. Or send a message to a coworker on linkedin whatever looking for information about that girl and they gave it to you? I'm curious :P

Veronica Mars style social engineering does tend to work.

So the actual method that worked was "another photo" mentioned by grecy https://news.ycombinator.com/item?id=6369669 an hour ago?

This method likely would have worked by itself. The method that worked sooner wasn't just "another photo" found online of her friends as grecy mentioned. It was a photo we had taken ourselves, and it didn't have anyone else in it. But I'm not ready to tell Justin more details about it.

This strikes me as odd, albeit a clue. You had a photo of a girl you'd presumably never met. A photo you'd taken, that you didn't know was her at first.

They went to the same event, took some photos. And in checking their photos, see that the same girl was in their photos too. Then they saw who she was with, and were able to locate a friend of hers. From locating a friend of hers from this second photo, they located her.

"didn't have anyone else in it" - seems no one else was in the photo with her.

Perhaps she was doing a presentation, so was alone at the front of the room. The photographer, being in the audience, would obviously know which presentation it was and from there its a quick look-up on the list of presenters.

Maybe her phone's contact list, call history, Facebook, Instagram, etc. or her business/credit card were visible in that picture?

So you had two pictures? But what does this give you? Unless the second picture was available on the internet it is just the same as the first one.

It entirely depends on what was contained in the photo..... Photos can contain information.

yah I was actually thinking of facebook ad just after I replied, with that criteria..only thing that turned me off from it what that you made it sound as highschool was a post-processor (validation) vs pre-processor (targeting)

Did that picture by include any kind of hint of a company she is working for?

No, there was no hint about what company she worked for. And she didn't apply to work at Elastic / Close.io either

she applied for work with your company, and you had her photo and info from the cv?

In the US CVs don't include a photo.

You were stalking her. Amusing story though

"stalk [verb] to follow, watch, and bother (someone) constantly in a way that is frightening, dangerous, etc."

No, we weren't. And she knew about it, was amused by it herself. No bad intentions.

Taking the third definition of off merriam-webster online doesn't really prove your point here. There is a reason why the title of the op was "Why Engineers Scare Me". I know this was all in good fun but please do understand why this is stalking and how the same technique can be used in very harmful ways.

stalk. verb: to follow (an animal or person that you are hunting or trying to capture) by moving slowly and quietly

stalk. slang defination: hound, spy, solicitation for a certain kind of information

> she knew about it, was amused by it herself. No bad intentions.

her opinion and agreement apparently doesn't matter, the internet knows better.

sophistry [ˈsɒfɪstrɪ] n pl -ries 1. (Philosophy) a. a method of argument that is seemingly plausible though actually invalid and misleading b. the art of using such arguments 2. subtle but unsound or fallacious reasoning 3. an instance of this; sophism

Your reply appears to accuse the parent of sophistry, but you provide an even worse argument for your claim than the parent does. It is not obvious to me how posting the definition of “stalk”, according to which the bet was not stalking, is an invalid or misleading argument.

I am directly accusing the parent of sophistry by selecting to post a definition of "stalking" that required malicious intent if not violence when that is not the totality of the definition, is not consistent with Merriam-Webster or Oxford dictionary and seeks to excuse their behavior by the omission. .

But you knew that.