Landing pages that host $500 giveaway contests generate 700% more email subscribers than landing pages not running contests, according to a ra new study by contest company Incentivibe. The report, which looked at data from March 15-April 15 from three million visitor interactions on 100 websites that ran monthly giveaways, revealed that Sundays were the busiest day for consumers to sign up as email subscribers, and Wednesdays had the lowest rate.