After all those years when pkg, the OpenSolaris packaging system, was solely network-oriented, the on-disk format is coming.
For those uninitiated to OpenSolaris intricacies - so far, when someone creates software for OpenSolaris and wants to distribute it, he has to either run his own install server (!) or provide the package in the legacy SVR4 format.
Would you like your software to be mirrored by other people? Good luck trying to convince them to run the pkg server.
Same goes for people running OpenSolaris in their internal networks - you want to update them but don't have access to the Internet? Run your own server! It takes several months to have a new network service approved? Bad luck, man ...
All this is soon to become the ugly but distant past. Check out the ON-DISK FORMAT PROPOSAL