I really like Sam Ruby's post on scaling down. Scaling down is a key concern of mine too, which is why I'm making this the weekend that my "all the perl I need for a webapp in one use declaration"-module goes onto CPAN.
Microscopic apps with almost zero footprint are a huge idea, it's the luxury version of Jot, the smart wiki that got consumerised into Google Sites.
Here's another super sweet example of scaling down: Jquery can insert the content of a specific DOM element from an external webpage into a specific DOM element on the current page in just one line
$("#links").load("/Main_Page #p-Getting-Started li");