Today, we all know Apple’s products, and a lot of us own one. Yet it is hard to identify the impact they or any of today's social-media giants have had on productivity. I was at first delighted with the convenience and freedom to read documents, check Twitter and search the web on the iPad mini I got in December, but it occurred to me recently that this was at best an incremental improvement over doing it on my BlackBerry or laptop. It also provides me with many more ways to waste time. As Tom Toles, the Washington Post’s cartoonist, puts it: