Area 51 allows me to take my great idea, find a community, generate an actionable proposal with demonstrated market relevance and deliver it to stack exchange inc.
What benefit accrues to me for participation in this process?
Area 51 allows me to take my great idea, find a community, generate an actionable proposal with demonstrated market relevance and deliver it to stack exchange inc.
What benefit accrues to me for participation in this process?
You get a community where you can ask questions to experts in the field you're interested in.
If you're an expert, you should also enjoy answering said questions.
As an added bonus, if the site gets really popular and you get lots of reputation, this could serve as a (perhaps somewhat controversial) advertisement of your skills, which you could put on your resume / CV if you're a professional in this domain.
Sure, you're giving your ideas to Stack Exchange and they may make lots of money off of it, but I'm willing to bet that most people making these proposals don't have the know-how and/or time (and/or other stuff) to get such a site off the ground (or even to sell it to someone who does), not to mention that Stack Exchange has a huge community already and is known for its quality - and rather significant problems with starting such a site would be marketing and convincing users that this new site would be better than what they're currently using, not to mention that your idea might just be bad - you could straight-up waste lots of time and money on it in trying to get it off the ground yourself, where-as you could've just taken the no-risk, no-reward option.
If you think you can profit from your site idea, giving it to Stack Exchange for free would obviously not be the way to go.
Well, you don't really have a site idea as such, just a scope definition. Think of it this way - Stack Exchange design and create the site (the question-answer interface, how users interact with each other, the voting mechanism, the commenting system, the reviewing system, the privilege hierarchy, hosting the actual site, etc.), you only provide the scope - while a site may not be able to exist without a good (well-defined, popular) scope, I certainly consider that to be a fairly small part of the whole thing (although some may certainly disagree here).