How many millions have lapped up sordid details of the private life of a certain Welsh winger? And yet, how many of those same people would appreciate outsiders nosing into their affairs and spraying the dirt all over the red-tops?
For marketers, too, privacy is a hot topic, and getting hotter.
Not so long ago, The Henley Centre did some research on the paradox at the heart of this issue. For example, people were incensed when their bank charged them for going into the red. When it was suggested that the bank could warn them that they were about to go over their limit, however, some people found this too intrusive. The banks couldn't win.
Now marketers have access to millions of lives lived in public, thanks to social media. In theory, this would allow brand-owners to carefully target their messages, based on data freely supplied by the consumer.
The reality is less neat. Some of Facebook's targeted ads make sense, such as 'Win a £20,000 wedding'. Others are nonsensical, if not offensive. How about: 'Meet men in your postcode'?
Such irritants aside, Facebook has a bigger problem. People are increasingly fed up with the company's cavalier treatment of their privacy. It seems Facebook's founders (young, American, well-educated, confident) just don't get it when it comes to people who are not like them. In Japan, the culture is more avatar than open book, while middle-aged Brits are living up to the stereotype of English reserve.
Smart marketers whose audiences cover a broad demographic have always been sensitive to the cultural norms of different age-groups. It is a lesson Facebook would do well to heed.