DeLi Linux stands for "Desktop Light" Linux. It is a Linux Distribution for old computers, from 486 to Pentium MMX 166 or so. It's focused on desktop usage. It includes email clients, graphical web browser, an office package with word processor and spreadsheet, and so on. A full install, including XFree and development tools, needs not more than 350 MB of harddisk space.
The trick is, that DeLi Linux uses only "lightweight" alternative software. If you are looking for the newest KDE, GNOME or Mozilla, DeLi Linux will not make you happy. The test computer is a 486 laptop with 16 MB RAM, and all apps which comes with DeLi Linux are running smoothly.