Vadim's comments aren't entirely accurate.
For instance the content repository does provide a generic, system-wide service. He may be confused because the CMS was originally a standalone system and he may not understand the fact that the CMS/CR split came about when it was integrated into ACS 4.x. Of course that generic facility is a bit light on Tcl API ...
The comment on its not being transparent to developers because one needs to write versioning code for each subtype is only partially correct. The insert views built for each content type handles the creation of new versions though they're inconsistently used in the toolkit. You do have to handle blobs directly but that has nothing to do with versioning, but rather Oracle limitations.
