The importance of accuracy depends on the particular use case geospatial data is developed for. For example, being several few meters off might be ok for a local urban planning department that only needs to know the relative position of buildings and roads but could result in costly errors for, say, a Department of Transportation that requires engineering-grade accuracy.
Since I wrote the last post I've had a hard time finding a single place where I can find information about mapping/accuracy standards. So, I thought it might be helpful to start a simple directory of relevant sites. Please feel free to check it out and let me know if you're aware of any other sites that belong on the list. I know I'm only scraping the surface, so additional state, national, or private specifications and standards additions would be appreciated.
For those interested in production-level mapping, be sure to check out the "GeoBC Crown Registry and Geographic Base" (that is a mouthful) standards and specifications page. It has a wealth of content, from digital camera specifications (e.g. down to the nuts and bolts of camera calibration specs) to aerial triangulation, DEM, orthophoto specs and more. They've done a great job of putting it together all on one cohesive site.