More than half US adult mobile phone owners used their phones to help in store in Christmas shopping

"More than half of adult cell phone owners used their cell phones while they were in a store during the 2011 holiday season to seek help with purchasing decisions. During a 30 day period before and after Christmas:
38% of cell owners used their phone to call a friend while they were in a store for advice about a purchase they were considering making
24% of cell owners used their phone to look up reviews of a product online while they were in a store
25% of adult cell owners used their phones to look up the price of a product online while they were in a store, to see if they could get a better price somewhere else
Taken together, just over half (52%) of all adult cell owners used their phone for at least one of these three reasons over the holiday shopping season and one third (33%) used their phone specifically for online information while inside a physical store—either product reviews or pricing information."

Source:  Data from Pew Internet & American Life Project, 30th January 2012