Well , Tom Hanks being associated with the App definitely drove a lot of traffic to it. But would you consider this as an endorsement ? Like Britney spears endo

Well , Tom Hanks being associated with the App definitely drove a lot of traffic to it. But would you consider this as an endorsement ? Like Britney spears endorsing Pepsi ,where you arent involved in any of the development process and simply show up in an Ad ? Looks like this is an App that Tom Hanks wanted to make himself out of his love for old and archaic Typewriters* , did not have CS Skills for it , hired an agency and got it done! ( some other articles do mention that he owned a personal collection of vintage typewriters) Definitely more than an endorsement , but yeah the app has a celebrity appeal to it ( like how Super Copters would now get a lot of press , just because its from Flappy Bird's Dev ) . A fair amount of effort is involved in building one's brand before things you do gain automatic traction.