Class::EHierarchy is intended for use as a base class for custom objects. The objects need one or more of the following features: orderly bottom-up destruction of objects, opaque objects, class-based access restrictions for properties and methods, primitive strict property type awareness, and alias-based object retrieval.
The Paranoid modules provide a number of routines that are intended for use in strict and taint-safe scripts. The modules cover a variety of tasks from command-line argument parsing to process and network management. All of the modules use a debug trace framework for diagnostic output that is easily used and extended for application code as well.
The metric implemented in the Image::Density Perl Module estimates the density of data where there is data, and has a reasonable correlation with goodness as judged by humans. That is, if you let a human look at a set of images and judge quality, the density values for those images as calculated here tend to correlate well with the human judgement (densities that are too high or too low represent "bad'' images). It is intended for use on bitonal TIFF images, such as those from scanning paper documents.
Mojolicious is "Duct Tape For The HTML5 Web". It is powerful with no dependencies out of the box with RESTful routes, plugins, Perl-ish templates, session management, signed cookies, a testing framework, a static file server, I18N, first class Unicode support, and much more. It has a very clean, portable, and object oriented pure Perl API without any hidden magic and no requirements besides Perl 5.10.1. It has a full stack HTTP 1.1 and WebSocket client/server implementation with TLS, Bonjour, IDNA, Comet (long polling), chunking, and multipart support. It has a built-in async I/O Web server supporting EV pluggable event queue, Unix domain sockets, and hot deployment, perfect for embedding. Automatic CGI, FastCGI, and PSGI detection for any deployment situation. It has a JSON and XML/HTML5 parser with an advanced CSS3 selector support. The code is based upon years of experience developing Catalyst.