Above and beyond that, any non-trivial web architecture is going to involve multiple tiers of data and caching.
A given text object will exist in the primary database, in its replicas or clusters, and in backups. If the outfit is at all legitimate, multiple backups representing frequent points in time, stored in multiple locations.
A binary object (say an image, video, or audio file) may exist in its originally uploaded format, several variants of different size, resolution, sampling rate, etc., and is often served through some sort of a content distribution network (CDN), which will have its own content management interface. Some of these are surprisingly primitive -- web-based forms in which a few score objects might be entered at a time, if you're lucky. Even script-driven purge methods are frequently limited as to the number of objects which can be included in a single request, and the number of outstanding requests which may be pending.
Given the large numbers of individual objects, scaling variations, redundancy, etc., deletion overhead can easily scale to tens to hundreds of millions of objects in a relatively short period of time (days to weeks). Dealing with all of this is fairly non-trivial. Especially if the site architecture didn't take these needs into consideration.