Damn Small is small enough and smart enough to do the following things:
Boot from a business card CD as a live linux distribution (LiveCD)
Boot from a USB pen drive
Boot from within a host operating system (that's right, it can run *inside* Windows)
Run very nicely from an IDE Compact Flash drive via a method we call "frugal install"
Transform into a Debian OS with a traditional hard drive install
Run light enough to power a 486DX with 16MB of Ram
Run fully in RAM with as little as 128MB (you will be amazed at how fast your computer can be!)
Modularly grow -- DSL is highly extendable without the need to customize