David Veldt noticed something strange about the people that LinkedIn was suggesting he knew. Apart from connections with mutual friends and colleagues, it started suggesting people he had no connection to that LinkedIn should know about. For example, it suggested someone whom he had emailed with a few times once, and someone he followed on Twitter (he hadn't connected his Twitter account to LinkedIn).

It also suggested someone with the same name as his high school girlfriend. He was friends with the ex on Facebook, but LinkedIn told him that it never uses one's Facebook data.