Mike Dunn wonders what the Microspeak term parking lot means.
I'm not familiar with this term either, and the first document I turned up during my search was a PowerPoint presentation that said "Avoid using Microsoft jargon terms, such as parking lot and dogfood."
Yeah, that wasn't much help.
From what I can gather, the term parking lot started out as a term used during brainstorming sessions. You've got a bunch of people in a conference room tossing out all sorts of ideas. The traditional way of organizing the ideas is to write each one on a Post-It® note and stick it on the whiteboard. As more and more notes appear, you start to organize them by grouping together similar ideas.
Every so often, you'll run into an idea that, while good, isn't really relevant to the problem you're trying to solve. You don't want to throw it away, so instead, you designate a corner of the whiteboard to be the place to "park" those ideas for later consideration. That corner of the whiteboard is nicknamed the parking lot.
The term parking lot then began to be applied to the document that collected all of these "parked" ideas, so they could be circulated to a more appropriate audience.
The term then expanded to refer to any document which served as the official repository of assorted suggestions for future work or discussion. (Known to some people simply as The List.) For example, there is a SharePoint List titled Active Issues and the subtitle parking lot for discussion topics in weekly XYZ meeting. Each item on the list is assigned to a particular person and assigned a priority.
I can't find any citations for parking lot being used as a way to say something like "we'll talk about this after the meeting is over," but I can see how it could be related to the sense of parking lot I was able to turn up: The parking lot is the list of things that aren't really relevant to the topic at hand but which are still worth discussing. We just won't discuss them here.