Nearly one-third of Americans say while they are at a store looking at product, they tried to find a better deal on their mobile device, according to a new report from GfK Roper, conducted on behalf of SapientNitro. Thirty-three percent say while out shopping, they email or texted someone to tell them about an experience at a store, such as finding a deal or gift. Nineteen percent have used their phone to post something to Facebook, MySpace, Twitter or other social networking sites about their holiday shopping experience.