AIRWeb 2009: Fifth International Workshop on Adversarial Information Retrieval on the Web Proceedings of the 5th international workshop on Adversarial Information Retrieval on the Web, Madrid, Spain, April 21, 2009. The workshop proceedings were published as a volume in the ACM International Conference Proceedings with ISBN 978-1-60558-438-6. Invited Talks The Potential for Research and Developmen