“Aggregating” or combining data from multiple sources can actually reveal surprisingly specific information. You might not work for the Pentagon, but your data can be aggregated in the same way to de-anonymize you. Here’s a small collection of these surprising privacy failures:
The Classic Paper – Simple Demographics Often Identify People Uniquely shows that knowing just birth date, gender, and zip code is enough to uniquely identify most people. Netflix Debacle – An anonymous Netflix dataset was de-anonymized by correlating it with the IMDB database. Social Exposure – De-anonymizing social networks (by Arvind Narayanan) demonstrates how an anonymous Twitter graph can be re-identified using Flickr for auxiliary information. Your Words Betray You – Your choice of words in writing can be analyzed to uniquely identify you according to On the feasibility of Internet-Scale Author Identification. Location, Location, Location – The traces of your GPS location app, even your approximate location, is pretty unique. Outlined in Unique in the crowd, the privacy bounds of human mobility. Bitcoin is often thought of as an anonymous currency, but it’s surprisingly non-anonymous, considering its reputation. This is because a lot of information is contained in the public ledger that records all transactions. See also An analysis of Anonymity in the Bitcoin System. Source: Tozny Blog
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