1. A computer--implemented method for collecting event information, comprising: on a server system having one or more processors for executing one or more programs stored in memory of the server system so as to perform the method: loading a plurality of XML documents, each XML document specifying event parsing logic for a respective group of related events; storing in one or more parsing trees a representation of the event parsing logic in the plurality of XML documents, the one or more parsing trees including event parsing logic for parsing events in a plurality of groups of events; receiving events, including events in the plurality of groups of events; and processing the received events in the plurality of groups of events in accordance with the event parsing logic in the one or more parsing trees, wherein the processing of the received events in the plurality of groups of events is performed in accordance with stored program instructions that are independent of the parsing logic for the plurality of groups of events, the processing including storing event information for the received events, wherein the stored event information for at least a subset of the received events includes information determined in accordance with the event parsing logic in at least one of the one or more parsing trees.