The WebServices folder is showing you metrics gathered by the SOA Performance Management (SPM) extension from various supported SOAP frameworks, e.g. Axis. The metrics are described in the SPM documentation.
Client refers to "outgoing" web service calls, "server" to incoming calls. Outgoing calls (WebServices|Client) may also be reported under Backends but more detailed information (breakdown by namespace and operation name, SOAP faults) is provided under Webservices. Incoming calls (WebServices|Server) are usually reported under Frontends, too (because they are handled by e.g. the AxisServlet).
Ciao,
Guenter