"...Aside from Weblocks, three frameworks I know of do a good job dealing with control flow - Seaside, UCW, and PLT. Proper control flow management is difficult to implement - it requires continuations, which most languages don't support. Because frameworks with good control flow management are so rare, most people don't understand what they're missing. In this article I'll describe the problem and how it is solved in Weblocks using continuations. A live Weblocks demo that showcases a practical implementation of these concepts is available here...'