I know the web-shooters are mechanical ones but the webbing itself is it something Peter Parker has "somehow" created (in spite of logic given the properties of the webbing) or is the webbing produced by his body and he just collects it and puts it in the shooters? (As I recall one of the trailers shots shows some webbing coming out of a spot in the nape of his neck.)
It's something he invented himself originally, if I remember correctly. Of course, since comics like to change things slightly from time to time there was also a period where he produced the "web" because of the spider bite.
And I think in the Ultimate Universe, the "web" is something his father created and he improved upon.