Still searching for a killer app in Windows 10 Anniversary Update

A couple of days ago, as I was finishing the InfoWorld review of Windows 10 Anniversary Update, a good friend (and astute editor) asked me a very simple question: Where is the killer app in Windows 10?
After all, if folks are going to go through the pain and bother of upgrading from Windows 7 or 8.1 to Win10 -- and of climbing the learning curve once again -- there has to be a good reason for the effort, right?[ Your one-stop shop for Microsoft knowledge: Everything you need to know about Windo