Jason is a good personal friend and lives here in the Jacksonville Beaches area. Just wanted to mention that he does a lot of work to execute the concept, much more than is readily apparent. The job is not only wearing the shirt -- he spends hours producing original video content EVERY DAY -- engaging and retaining his audience is the main part of the job.
We can't all be Gauss but, then again, we're not in fourth grade anymore, either. You can sum over any range trivially: average of the endpoints times length of the range. The average of 1 and 365 is 183. There are 365 elements between 1 and 365 (both inclusive). 183 * 365 = 66795. Yay, right answer.
(There is a formula. I have a poor memory for formulas but am good at transforming English into them, so I just remember the English gloss.)
I'm decently impressed that Wolfram was able to spit out something equivalent to the right formula with only a little massaging of the inputs from me:
There's a famous possibly true story about Gauss having to sum the numbers 1 to 100 as a child. Most versions tell it that he noticed that 1 + 100 = 2 + 99 = 3 + 98 and so on, yielding a general formula of n * (n + 1) / 2, so you could probably skip Wolfram for this one. (Explanation: you have n numbers, on average each is equal to the first + the last divided by 2)
It's a simple business model - all it requires is an easily explainable idea ("I wear your t-shirt") and enough viral marketing in advance to drive the traffic that will drive the advertisers (ie, those who will pay you to wear their shirt).
I'm sitting on two other niches for basically this business model - planning on moving overseas next year at some stage, though, so will wait until 2011 to implement (by which I mean October 2010 to start marketing).
I'm sure we could all come up with some variants.
Edit: It also helps that it's most attractive to retail / mass consumer products, and that these are most in demand in the holiday season, and that the holiday season coincides with the end of the calendar year, so the most expensive dates are also the most valuable.
You could. After the Red Clip guy, the Million Dollar Page, and the woman who sold a tattoo on her forehead, this is becoming an old trick. Yet it still works!
66,795 is definitely not bad for wearing t-shirts. Not factored into that though, he receives 365 free t-shirts a year! That could be valued around 3650 ($10 per shirt)
Just sayin, Jason Sadler is an awesome dude. Anyone who chooses to do business with his company would never been dissapointed. It's well worth the price! :)