- Are the StackExchange processes e.g. around site creation and reputation management meant to settle into a stable state or are they meant to remain fluid (as in agile, domain-specific) in perpetuity?
"Stable state" sounds like death to me. Sure, things should be predictable if possible, but every new site launch (or even just proposal) teaches us something new from which to draw conclusions, and possibly use these conclusions to improve the whole thing. So you can be fairly sure that you haven't seen the end of the evolution as far as the site creation process goes.
- Are these processes written down in a single place, manual, or FAQ or are they the sum total of the latest stage of discussion on sites such as this one?
I would think that the Area 51 FAQ sum the whole thing up pretty well. Of course there are always points not laid out in the most detailed way possible. This is hardly possible though; after all, the more rigorously you put the site creation process into a cookie-cutter shape, the less flexible you are. Take Ask Patents for example (announcement post here), which didn't follow the standard Area 51 process. But in general, the Area 51 FAQ are a good place to start, and for questions/discussions about details, Meta Stack Overflow, Area 51 Discuss, and/or site-specific metas are the place to go.
- Would it be okay to use some process elements (perhaps with attribution but otherwise for free) in non-competing services or apps elsewhere? In other words: what is the patent situation (and what is/are the StackExchange business case/s -- I noticed somewhere that you seemed to have hired several new sales representatives lately)?
I think and hope* that the whole company agrees with me when I say that patents on things like the Area 51 process are utter crap. Period.
As to the "How do we make money?", see What is Stack Overflow's business model?, and also this quote from Joel's Series A funding blog post:
One of [the VCs we talked to], Brad Burnham, suggested that we don’t hard code our revenue model too early. If the platform creates value for a lot of people, he told us, we’ll have plenty of opportunites to make money that actually make the site better.
That reminded us of Stack Overflow Careers, where great programmers can leverage all the good work they do on Stack Overflow to get great jobs. It gives us an opportunity to make money and it actually makes the site better.
* but obviously cannot know with all certainty, so in the end it's just my personal opinion