HTTrack would seem to potentially be the start of a way to cache websites
separate and more durably from the rather limited scope of a browser's native
cache. This would be a great way of rebrowsing offline or even limiting the
loading time of sites when they are revisited, although ad revenue services
would probably be vehemently opposed.

This would be particularly useful, for example, for referring to craigslist
postings even after they have been expired / been deleted. Perhaps this could
also be integrated into a service like the Wayback Machine (archive.org).
Instead of caching all sites, there could be an option to setting a filter to
download to sites only from only a certain domain.

Anyone working on such a program?