The Service Catlogue preferences control which service catalogue instance is searched for services in the Service Catalogue perspective. These preferences can be changed by:
Base URL of the Service Catalogue to connect to
Base URL of Service Catalogue instance to connect to controls which service catalogue you are searching for services. Some institutions and groups will host their own instance of service catalogue. By default, Taverna will connect to BioCatalogue at http://www.biocatalogue.org/.
In general users should not change the value of this URL from http://www.biocatalogue.org unless they know that they want to connect to a different service catalogue.