Because the Internet is a public good and its numerous users are not charged in proportion to their use, it appears rational for individuals to consume bandwidth greedily while thinking that their actions have little effect on the overall performance of the Internet. Because every individual can reason this way, the whole Internet’s performance can degrade considerably, which makes everyone worse off. An analysis of the congestions created by such dilemmas predicts that they are intermittent in nature with definite statistical properties leading to short-lived spikes in congestion. Internet latencies were measured over a wide range of conditions and locations and were found to confirm these predictions, thus providing a possible microscopic mechanism for the observed intermittent congestions of the Internet.