The App::Cache module lets an application cache data locally. There are a few
times an application would need to cache data: when it is retrieving
information from the network or when it has to complete a large calculation.

For example, the Parse::BACKPAN::Packages module downloads a file off the net
and parses it, creating a data structure. Only then can it actually provide
any useful information for the programmer. Parse::BACKPAN::Packages uses
App::Cache to cache both the file download and data structures, providing
much faster use when the data is cached.

This module stores data in the home directory of the user, in a dot directory.
For example, the Parse::BACKPAN::Packages cache is actually stored
underneath "~/.parse_backpan_packages/cache/". This is so that permissions
are not a problem - it is a per-user, per-application cache.