More than half of email messages sent last week to promote Mother's Day offers, or more than 12,000 campaigns, had the word 'mother' in the subject line, according to email intelligence firm eDataSource. This wasn't a bad thing. In fact, according to the research, Amazon's "Amazing Deals – Jewelry Gifts for Mother's Day" saw a 43 percent open rate and Nordstrom saw a 42 percent open rate with the subject line "Pandora for Mother's Day".