Viktor Kojouharov was sick of constantly having html code snippets inside his perl code. He was seeing too many projects where the code was a messy mixture of perl, html, and in some places, javascript. Since he is familiar with the Gtk+ toolkit he decided to make something similar targeted for the Web.
He ended up with IWL which is, in Viktors words:
basically a graphical toolkit, or widget library, much like Gtk+ or the ETK library for enlightenment. The main goal of this library is to create a full blown RIA, without the need to write html in your code. When I started working on it roughly a year and a half ago, there was nothing similar existed for Perl. By using the library where I work, it has so far mostly achieved its main objective (and has also proven to be an excellent subject for my diploma thesis :))
If you are a Perl developer who prefers writing apps in a toolkit style like below, then IWL may be fore you: