I'm looking for a succinct one or two paragraph description of the Stack Exchange concept. Especially for non-techie types. I'd like to do more sharing/promoting of a few proposals in Area 51, but I'm running into the "eyes glaze over" syndrome.
I would simply say:
Stack exchange is a collection of websites where you can get your questions about a specific topic answered or help answering other's people questions. It differs from other websites - such as Yahoo Answers - by having higher quality content.
No need to dwell into things like reputation, community editing, etc. Probably your friends won't care unless and until they want to become avid users.
Also no need to use complicated sentences with buzzwords which are - at least to me - a huge red flag.
Just say what the website is.
Stack Exchange is a framework for building focused, subject-specific, question and answer sites with crowd-sourced ranking and moderation.
Area51 is a tool for bootstrapping the crowd-sourced engine by establishing a small but working crowd for seeding the sites. This is accomplished by getting the crowd to help in defining the sites then collecting commitments from user to participate.