what do the strat controls do?

One is for the neck, the other for the middle. The bridge pup doesn't have a tone control.

So you end up using only the neck tone control in position 1 (neck pup only), both tone controls in position 2, only the middle tone control in position 3 and 4, and in position 5 (bridge only) the knobs are just decorations.

One is for the neck, the other for the middle. The bridge pup doesn't have a tone control.

So you end up using only the neck tone control in position 1 (neck pup only), both tone controls in position 2, only the middle tone control in position 3 and 4, and in position 5 (bridge only) the knobs are just decorations.

Not totally true. It depends on the model and place of manufacture.

Here's a link to a page that gives the wiring for all the various Fender models. Some have no bridge tone, some have bridge & middle - there may be others, I haven't looked at every wiring diagram.

the new strat american deluxe series features the S-1 control switch that offers an incredible amount of tonal possibilities

http://www.fender.com/products/s1/pdf/AmericanDeluxeStratSSS010-1200.pdf

One is for the neck, the other for the middle. The bridge pup doesn't have a tone control.
I was under the impression that the middle was the one that's always full-out... no?

Not in my experiance of playing my Strat.

There are various wiring schemes for strats, that's true enough. The variations will be in the 'American Standard' line - they've wired that a few different ways.

So in general: standard strats are wired for neck & middle; deluxe strats are wired for neck & middle/bridge. Models with humbuckers in one or more positions, and the 'signature' models are all over the board.

A few strats don't even really have two tone controls (although some of those will have two tone knobs!) On those, one is a master tone control, and the other is usually a mid-range boost.