"Get out of #Jail Free Card" by Mark White is a $9.99 eBook that promises to reduce your workweek from 70 to 40 hours.
Mark White has spent two years testing the methods in his new book, and now he’s made it available to workaholics worldwide.
This short book is designed as a tool rather than as an armchair diversion. It shows you the faster, easier, natural way to take back your life.
One of the tips in the book is "No Phone Calls," which mentions Basecamp:
I am not the type of person who uses the phone a lot. I’ve learned very early to transfer complete business related communication to email. Written trace of a correspondence is much more practical, because you can keep track of who said what and when. Tools like Basecamp just brought it up to a higher level.