Please can someone explain what 'nodes' are to me?

Sorry, I’ve read the manual and it makes no sense to me whatsoever! I think i might be able to piece it together in my head if someone explains in very simple terms what they roughly are! :spin:

ta, in advance.

Nodes are a gui element for organizing data. They each do a specific task, and they act as a group to do something. They are similar to a flowchart. You start with one thing and you send it to another node to do something. In blender they are used for making complex materials and for image editing/compositing. Here is a link for materials:
http://wiki.blender.org/index.php/Manual/Using_Nodes
and one for compositing:
http://wiki.blender.org/index.php/Manual/Using_Compositing_Nodes

At the basic level, compositing nodes are graphical processing programs that do one simple thing to an image. they take an image in, do something to the colors/pixels within the image, and then pass it on. Egan gave u the links to text.

Material nodes make procedural materials change color as they are applied to a surface. see http://wiki.blender.org/index.php/Manual/Node_Materials.