All Esper user discussions take place on Esper Usage Google Group.
For .NET NEsper specific questions please use NEsper Usage Google Group.
You may also post to Stack Overflow. Please assign the "Esper" tag when posting to Stack Overflow.
If you cannot access Stack Overflow, please create an issue in Github.
Archived Mailing List
As of March 5, 2015, we have moved away from the Codehaus mailing list.
The old Codehaus mailing list archive is at EsperMarkMail Archive. The Nabble archive is an alternative at Esper Nabble or search for "Esper Nabble".