Techniques?

I continually read references to techniques in solving sudoku puzzles. I was under the impression that sudoku puzzles were meant to be solved by using pure logic, eg. this number can't go in that row, so to fit in the square, it has to be in the only open column, which means that it can't be in the similar column two squares down, therefore it must go on the other side in the next square, so it must fit in the middle column of the bottom square, etc. and so forth. I'm not aware of any techniques, but I find solving them based purely logically suits me fine. I also find that guessing defeats the purpose.

Also, I noticed that you allow for "possible answers for this square". I find it easier without "possibles", eg. when I can, I'll work out that, say, these two boxes can only contain the numbers 4 or 6, so, given that I have already deciphered that other boxes in the square contain, say, 5,3 and 1, I automatically surmise that the empty boxes must be filled with 2, 7, 8, and 9, and then by using the existence of these 4 numbers in parallel squares, I can strike each one off until the square is solved. I only put a number in a box once I have logically deduced that that box is the only possible location that it can be in.

Is there some Sudoku sub-culture that I've completely missed? I'm pretty sure that I'm getting it right, because each row, column and square contains all 9 numbers. I feel a bit confused by this.