The main goal of the Lively Kernel is to bring the same kind of simplicity, generality and flexibility to web programming that we have known in desktop programming for thirty years, but without the installation and upgrade hassles than conventional desktop applications have.
The Lively Kernel places a special emphasis on treating web applications as real applications, as opposed to the document-oriented nature of most web applications today. In general, we want to put programming into web development, as opposed to the current weaving of HTML, XML and CSS documents that is also sometimes referred to as programming.
If you are interested in Dan Ingalls way of reasoning, read "The Design Principles Behind Smalltalk" -- a document, which is more than 25 years old and still worth reading. Two other members of the Lively Project, Tommi Mikkonen and Antero Taivalsaari, have written another interesting paper, which might help understand, why they developed Lively: "Web Applications - Spaghetti Code for the 21st Century".
By the way, my students and I started analyzing Lively in my course "Modeling Software Architecture". I'm curious on the insights we will gain.