Email Subject Line Test: Which Otherwise Identical Message Got More Clicks (Not Opens) – Dash vs. Colon?
Very nice experiment.
My gut told me version A is a better winner, as dash works as "call for action". And I was sorta right.
Version A made it by almost 15% over the version B in clicks, however, version B received more open by more than 12%. I don't have a good explanation for that, but that's an interesting thing to come by.