It would be helpful to set up a confirmation email that would be sent once an email campaign is sent. This way we wouldn't have to log into Marketo to check the status of an email to see if it was sent.
The email would say something similar to this:
Your email campaign, named "sample", was sent on 08/22/2014 around 9:57 AM EDT.
Below is a copy of the HTML version your subscribers received.