Shared Listener as the name suggests can be used by 2 or more trace sources(eg. Say one logs Messages and other logs Errors, Warnings etc) by using a friendly name. But if both of them plan to use the same tracefile,

Then the advantage here is you don’t have to repeat the Type, culture etc for the filename . See the highlighted portion below, this could be shared by different trace sources

These are the differences between the Listener and Shared Listener as per MSDN (http://msdn.microsoft.com/en-us/library/ms229501.aspx)

<sharedListeners> Contains listeners that any source or trace element can reference.

·         These listeners do not receive any traces by default

·         It is not possible to retrieve these listeners at run time.

·         Listeners identified as shared listeners can be added to sources or traces by name.

·         Adding a listener to the shared listeners collection does not make it an active listener. It must still be added to a trace source or a trace by adding it to the Listeners collection for that trace element