Facebook's Cookie Expiration Policy

John Sutter: Cookies expire, right? He says there are browser restrictions on this or obviously Facebook wants to have its cookie last as long as possible forever if possible. Chrome and Safari will restrict the cookie expiration period to be I don't know if it's seven days 14 days, he says. That means say your Facebook user clicks through an ad navigates the website maybe add something to the card but ultimately doesn't purchase because their cookie expired. They come back maybe a few more days, but it's on day eight, the day after their cookie expired on day seven and then they purchase. The company cannot tie that user that purchase back to that original ad click and cannot report on that