I want to run campaigns for a different domain that has a different email address. Is this possible?

Yes, absolutely!  By default all emails are sent from our domain with something like "[e-mail]."  Now, every campaign has its own email settings for the REPLY-TO field. To change this, go to the "Rewards" tab and just paste in the address you want to use for that individual campaign. You can run multiple campaigns on multiple websites at the same time, by the way, so go crazy with it!