In distributed environments, including Web Services, application integration, and personalized content delivery, XML will be used as the wire format in which data to be exchanged is encoded. In this emerging infrastructure, XML message brokers will serve as central exchange points for messages sent between applications and/or users. Three of the main functions of such brokers are: filtering, transformation, and routing.

Filtering matches messages to predicates representing interest specifications.
Transformation restructures matched messages according to recipient-specific requirements.
Routing involves the transmission of the customized data to the recipient.
YFilter aims to provide fast, on-the-fly matching of XML encoded data to a large number of interest specifications, and transformation of the matching XML data based on recipient-specific requirements. Over the past two years, it has been developed into an efficient query processor on streaming data that high-capacity XML message brokering systems can be built on.