The advent of fast, cheap networking has made it possible to store information at remote third-party locations, where it is intermingled with that of other users. For example, many people no longer keep their email primarily on their personal computer, and instead use a web-based email provider, which stores their messages along with billions of messages from and to millions of other people. Similar services exist for photographs, slide shows, computer code and many other types of data. As a result, people now have personal data that are stored with that of innumerable strangers. Seizure of, for example, Google's email servers to look for a few incriminating messages could jeopardize the privacy of millions.
It's no answer to suggest, as did the majority of the three-judge panel, that people can avoid these hazards by not storing their data electronically. To begin with, the choice about how information is stored is often made by someone other than the individuals whose privacy would be invaded by the search. Most people have no idea whether their doctor, lawyer or accountant maintains records in paper or electronic format, whether they are stored on the premises or on a server farm in Rancho Cucamonga, whether they are commingled with those of many other professionals 1177*1177 or kept entirely separate. Here, for example, the Tracey Directory contained a huge number of drug testing records, not only of the ten players for whom the government had probable cause but hundreds of other professional baseball players, thirteen other sports organizations, three unrelated sporting competitions, and a non-sports business entity—thousands of files in all, reflecting the test results of an unknown number of people, most having no relationship to professional baseball except that they had the bad luck of having their test results stored on the same computer as the baseball players.