If you are deploying this on FME Server then you can get the username using the parameter $FME_SECURITY_USER I believe.
I don't know if we have a Desktop parameter or env variable for the currently logged in username, but I did find that I could obtain it using Python:
import fme import fmeobjects import getpass # Template Function interface: def processFeature(feature): feature.setAttribute("MyUsername",getpass.getuser()) pass
So once I get my username I could tag @safe.com on the end to give me my email address.
I hope this is what you were looking for.