When we started to do email campaigns, we had open rates of around 36% with corresponding high click-through rates. Pretty damn high. Then management started to abuse the hell out of it by over-emailing everyone. We either had people unsubscribe like mad or just ignore/not open. Our open rates went down to about 5%. We had over half our list unsubscribe.
Every time we had an event or something going on the message was always the same "I want this to go out to everyone." I'd be like "We need to email far less, and target to people's interest when we do." Have an event coming up? "I want an email blast going out EVERY DAY for a week before the event reminding people about it.
So eventually the big guy is despondent over the super low open rates. We end up contracting with a social media expert company to develop a strategy for us, that cost us $40,000. Their biggest recommendation? Cut down on the number of emails we send out, and target them to interested audiences.