In this work we discuss how to provide information filtering (pub/sub) functionality over peer-to-peer structured overlay networks by presenting two approaches we developed. Both approaches utilize the Chord DHT as the routing substrate, but one stresses retrieval effectiveness while the other relaxes recall guarantees to achieve lower message traffic and thus better scalability. We highlight the main characteristics of the two approaches, present the issues and tradeoffs involved in their design and compare them in terms of scalability, efficiency and filtering effectiveness. Finally, building on our experience from these systems, we highlight the advantages and disadvantages of each approach and state the lessons we learned. 1.