Ive used Damn Small Linux (DSL) quite a bit in the past. Before getting my laptop I used to use it to be able to get a Linux desktop at my in-laws house. I decided I wanted to try out some of these other lightweight Linux distros that everyone is always talking about.
Read the comparison here
Overall, Ive been quite surprised. I assumed that these three distros would end up being pretty much exactly the same. Yet each of these have been quite different and each has had more software than the last. They tend to load a lot faster than other Live CDs such as the venerable Knoppix or more recent LiveCDs such as Ubuntu or Fedora. This makes a lot of sense since these smaller distros are able to load completely into RAM. Not only that, but they are also great for the environment as you can use them to power older computers that choke on Windows XP, Windows Vista, or even some of the more modern Linux distros. For people like most of the older generation who only want to surf the net and send emails, there isnt anything out there that cant be done by these small distros. I think the surprise winner is Puppy Linux 3.01. Feather Linux is also a good choice and comes in second. DSL comes in last because I think that 50 MB for a disto is becoming quite limiting, it couldnt connect to the net for me, and I think that the old computer to be resurrected is a standard that is slowly moving. So less and less do we need to be as tight with our RAM as with DSL and we can get away with (relatively) larger Puppy Linux and Feather Linux.