I haven't found anything on the ArcMAP forums. Is there any way to represent related tables on arcGIS.com web maps? I have a geodatabase that has related tables, but so far I am only able to show the feature classes and not the related tables.
ArcGIS Online does not currently support related tables. However, it was announced at the User Conference on Sep 11, 2014 that they are working on this functionality and hope to release in in Q4 2014, or maybe Q1 2015.
At the time of writing, ArcGIS Online as a hosting platform does not support related tabled. However, ArcGIS Server does.