Rebol is designed for the exchange and interpretation of information.
What impressed me with REBOL was how easy it was to create graphical application and how elegant the language was.
However, by reading more about the author, I realized that maybe the true purpose of REBOL was different.
http://www.rebol.com/bio-carl.html (emphasis mine):
REBOL offers a unique approach to distributing, sharing, and processing information across the Internet. At its core, REBOL is based on a special language technology that uses relative expressions to create dialects for intercommunication in much the same way that people communicate. The approach allows a computer to "understand" the meaning and how to interpret information sent from other computers. The result is a software technology that is not only many times more efficient and easier to use, but one that extends the Internet beyond web services to a simpler and more integrated model of distributed personal computing.
And it seems that Carl decided to push his goal even further by currently working on ASON and AltScript by Carl Sassenrath (as of 2021). As long term goals, he wants to create a non-SQL database (AltBase) and a new OS (AltOS). I'm pretty excited about the OS.