The root thingee that you see ad nauseum in this website is a reference to the concept of the
RHIZOME
"A rhizome as a subterranean stem is absolutely different from roots and radicles. Bulbs and tubers are rhizomes. Plants with roots or radicles may be rhizomorphic in other respects altogether. Burrows are too, in all their functions of shelter, supply, movement, evasion, and breakout. The rhizome itself assumes very diverse forms, from ramified surface extension in all directions to concretion into bulbs and tubers ... The rhizome includes the best and the worst: potato and couchgrass, or the weed." (Deleuze & Guattari, 1987, p. 6- 7)
A concept put forth by Deleuze and Guattari. The rhizome is, literally, an underground root. However, it has major implications beyond the field of botany. The rhizome is a model of the way we reason in a postmodern world. All ideas are interconnected by invisible (underground) roots and connections. As opposed to traditional, linear thinking, the rhizome allows for the multiple ways in which ideas are connected.
For more information, check out:
What Douglas Kellner has to say about the rhizome
A nice compilation of links from the University of Texas at Arlington (who'da thunk it)