Yes he did literally nail the 95 Theses to the door, but remember he wasn't the first to nail things to the door of that church, it was somewhat common. It was almost certainly taken down at some point but it was not his only copy offthe 95 Theses, he had simultaneously sent copies to the local bishop and archbishop, complaining about the issues he raised in the Theses.

The posting of the Theses was probably the spark that caused the reformation but even if this was taken down, many had already read the ideas and Martin Luther could still speak to people. Once it was translated from the Latin it was written in to languages people could understand and distributed via the printing press, sponsored by some of Martin Luther's friends, it was nearly impossible for the Catholic church to stop his ideas spreading, leading to the pope himself issuing an official counter argument 2 years later.

So yes, although it wasn't his only copy, the copy nailed to the church was the most important one that kicked everything off.

Arthur Koestler wrote in The Sleepwalkers that basically Gutenberg did it. In the sense that the whole thing was made possible by the new printing presses and the general lack of copyright and similar stuff. Luther would write a flyer, a short treatise, a booklet, something. He wrote a lot of them. A travelling merchant would take a copy to another city and have it printed and sold for money - not necessarily because he believed it, but because he could sell it for money and not even have to pay royalty to Luther or something. Then another merchant would take it to another city etc.

You could say that "pirated" copies of his work were sold for money :)

Source: Arthur Koestler: The Sleepwalkers.