This week marks fifteen years since our book, Content Rules , hit store shelves.  From the moment Ann Handley and I first met to discuss working together, we were committed to writing a book that would not be outdated the moment it was printed. Instead of focusing on tools, we’d focus on mindsets and strategies that would stand the test of time. It still gives me a giggle to think about how, within the year between the first edition and our paperback edition, Instagram launched, and we had to add a section around social photography since it was clear that it was going to be a significant new addition to everyone’s marketing efforts. I know we accomplished our goal of writing a timeless business book, because it is still being used in classrooms and offices around the world. It isn’t uncommon to find a new reader singing the book’s praises online every few weeks.…