The rapid increase in smart phone capabilities has introduced new opportunities for mobile information access and computing. However, smart phone use may still be constrained by both device affordances and work environments. To understand how current business users employ smart phones and to identify opportunities for improving business smart phone use, we conducted two studies of actual and perceived performance of standard work tasks. Our studies involved 243 smart phone users from a large corporation. We intentionally chose users who primarily work with desktops and laptops, as these "non-mobile" users represent the largest population of business users. Our results go beyond the general intuition that smart phones are better for consuming than producing information: we provide concrete measurements that show how fast reading is on phones and how much slower and more effortful text entry is on phones than on computers. We also demonstrate that security mechanisms are a significant barrier to wider business smart phone use. We offer design suggestions to overcome these barriers. © 2011 ACM.