SkinnyDebbie is what I am calling a “distribution flavorizer”: A set of small packages that will configure a standard Linux distribution (a Debian Network Install in this case) to match a given target “flavor”, using as much as possible the packages and repositories that are already part of and maintained by that distribution.
This is in contrast to a “derivative distribution”: A complete Linux distribution that maintains a full set of repositories mostly mirrored from a parent distribution with some package enhancement, substitution, and additions.
Why make SkinnyDebbie a “flavorizer” instead building an independent distribution? Simple: a “flavorizer” approach lets SkinnyDebbie be 98% pure Debian, and that lets users benefit directly from the security updates, miscellaneous improvements, and community support of a major distribution.