Why is XML useful for free software ?

• Well defined, strong I18N support, open specification
• vendor independant, and getting wide industry acceptance
• ease reuse of data between projects
• allow to share code

A few examples:

• config file format (GConf, gphoto, ...)
• data format (Gnumeric, abiword, advogato, packages, ...)
• client-server protocols (WebDav, rpmfind, ...)