I believe I have invented a new type of puzzle...
What is its name?
Begin by solving the 16x16 sudoku; each of the digits 1-16 must appear exactly once in each row, column and thick-bordered 4x4 box. Then apply some grid-deduction-deduction (!) and discover its name!
Notice that in the second-step grid-deduction puzzle (solved by @athin) there were several trivial 1's that could be resolved immediately. Clearly they were not that important to resolving the rest of the grid - but they must have been included for another reason, right??
The message that has been encoded in the final solved puzzle is 16 letters long.
Consider the trivial 1 in the bottom row of the second-step grid-deduction puzzle... If this had been omitted, 2 letters in the hidden message would have been corrupted and unreadable.
Other puzzles in the 'This new puzzle type needs a name' theme: 01, 02, 03