Question came up because I saw this was labelled as off topic: How to save python Rtree spatial index to file?
I've always thought of GIS.SE as a QA site for everyone working in/with data in a spatial context; developing, scripting, or working with end-user tools that deal with spatial data.
Since Rtree is a core component of dealing with larger spatial datasets (or perhaps more broadly 2-dimensional datasets), I feel like it would fit squarely within GIS.SE's scope.
The closing of that question and some other recent experiences suggest to me that those developing tools or scripting with spatial data ought not use this site but rather Stack Overflow.
Is it the intent of the moderators to curate GIS.SE specifically for end users of GIS tools, and to push that all other spatial data-related scripting and engineering questions move over to SO?
If so, where do we draw the line?
Does interacting with the APIs of other popular Toblerity libraries, like Shapely, constitute SO questions while using ArcPy methods consistute GIS.SE-friendly questions?
Does information architecture as it relates PostGIS spatial data storage belong in SE while higher-level query issues belong in GIS.SE? Or should all be moved to SO?
If someone were developing a module or adding functionality to underlying QGIS features, would those questions belong in SO while only the questions from an end user clicking through the UI workflow belong here on GIS? This question (Where do questions about QGIS plugin development belong?) suggests that it all ought to be here, which furthers the confusion.