Courtesy of the 100 Years Ago Today Subreddit and the 365 Days of Motoring website we learn that today was the day that Ford introduced the TT, that is, its Model T based pickup truck. Or rather, truck, they weren't all boxed trucks, but trucks in general.
It wasn't simply a Model T conversion. The chassis was heavier than that of the Model T, reflecting its intended use.
Apparently it was originally just a chassis, and the body was up to the owners. According to 365 Days of Motoring, Ford offered the complete package, body and all, starting in 1924. The grand total for production for 1917 was three. Yes, only three, but the following year over 40,000 would be built and numbers were always higher than throughout its ten year production run.
Pickups have always been a big deal in the American West. Somehow, however, they've come to be a huge deal in the American automotive market in general and make up a big percentage of vehicles sold each year.