[jmathai]

I'm not sure how LinkedIn does it but their "recommendations" are very spooky.

I get some really odd ones like the property manager we pay rent to. I've only ever emailed or called him.

I presume he gave LinkedIn access to his email contact list but based on the number of these creepy recommendations a lot of people I email with must do it.

Even more spooky are the recommendations to connect with people I don't know but have names that match people I do. Anyone know how they do this?

[uladzislau]

LinkedIn does that by cross referencing cookies, contact lists, email addresses. The same way Facebook does. People just used to expect more integrity from LinkedIn.

[jmathai]

They've been doing this for a while....

[Q4273j3b]

Surprisingly simple math (like https://news.ycombinator.com/item?id=5854593), the data you just described, and also IP addresses. I wouldn't be surprised if they also use browsing habits (search history on LinkedIn, profiles visited on LinkedIn). So they might guess the friend's name from the data, but not know which exact profile out of several identically-named profiles represents the person you know.