Some court transcripts from the McVeigh case contain interesting information about real-life anonymous systems. See http://www.cnn.com/US/9703/okc.trial/transcripts/may/050697.eve.html Did you know that money orders are not so anonymous as you might think? On the order itself are digits identifying the post office where the order was purchased, as well as the date of purchase. Also, a private company testified on their money order service, and it comes out that they keep a computerized record of every money order purchase in a central database. Eek. And read about a real-life instance of traffic analysis of phone calls based on timing correlations. This one really happened, folks (though it was by mistake). Also, read about how a company offering prepaid debit cards searched through billions of records to find all phone calls to or from a certain number, etc. Read about how they entered a disk containing information on 100,000--200,000 phone calls (!) into evidence. (Note: contents of calls are protected by law, but traffic analysis specifically is allowed, far as I can tell.) And you value your privacy? Too bad!