MasterCard uses sky-writing to promote its social media campaign 
As part of its Priceless Surprises campaign, MasterCard is giving 12 lucky cardholders the opportunity to write their love messages across the sky this Valentine’s Day. Cardholders simply must use the hashtag #PricelessSurprises when posting to Twitter. MasterCard will then randomly select cardholders in Dallas, New York, Los Angeles, and San Diego to receive a free sky-writing experience.