YSK that if you pay with a credit card at Target, the company sells your in-store purchase history to advertisers

Many people are unaware of how invasive Target's privacy policy is and how it builds profiles across multiple platforms to sell your data to advertisers. Target attempts to link: - everything you buy in store (including the Target pharmacy) - anything you say on your various interweb accounts - data for sale from 3rd parties on your age and income

This creates a rich dataset that can result in very deep targeting across the interwebs (and thus lots of revenue for Target).

For example, this woman mistakenly attributed the ads she saw after experiencing a burn (8th paragraph) to FB listening through her phone's microphone, though the true source was likely the purchase she made at Target.

Source: Target's own privacy policy. Here are some highlights:

We merge data collected from our own websites, [...] demographic and other information regarding your likely commercial interests from third parties; and in-store transaction data.

We collect data that is publicly available. For example, information you submit in a public forum (e.g., a blog, chat room, or social network) can be read, collected or used by us and others, and could be used to personalize your experience.