I'm kinda new to perl, what's the best way to figure out what a lot of these packages actually do? The content of the readme's are hit or miss for quite a few. I'd be curious if there's a collection of CPAN modules complete with helpful abstracts. Or maybe just point me to the right place, if I'm missing something.
If you click on the name in the top-left corner, you'll be taken to metapan.org. Click on a module under "Modules" to view its documentation. The first module is often the "main" one.
There are also Tasks::*, such as [1], at CPAN that can be a good start when you're looking for modules for a particular purpose.
Most people don't generate a README file. Instead, read the POD, which for a distribution Foo-Bar is usually located somewhere like http://search.cpan.org/perldoc?Foo::Bar
... because CPAN is the only package index with a map visualization?
edit: That map visualization seems to show CPAN package namespaces sized relative to the rest of CPAN. This does nothing to visualize the size of CPAN itself, therefore I don't see how "That's why we use Perl" is a valid comment in response to this visualization seeing as it seems to be implying that they use Perl because of the breadth/depth of CPAN.