Shoppers seem to be just as enthusiastic about shopping on their computers and smartphones on Cyber Monday as they were about finding deals over the weekend. Online sales on Cyber Monday, which was started in 2005 by a retail trade group to encourage Americans to shop online on the Monday after Thanksgiving, were up mid-afternoon by 15 percent from a year ago, according to data from IBM Benchmark. Meanwhile, sales from mobile devices were up 7.4 percent. The group did not give dollar amounts.