All meaning is intertextual. No text is complete or autonomous in itself; it needs to be read, and it is read, in relation to other texts. - Jay Lemke

A genre is maintained by the conventions of a community, and in most cases serves specific functions within the system of practices of particular institutions of that community.

Human communities are ecosystems. Ecosystems are biological, chemical and physical systems. The physics, chemistry and biology of complex self-organizing systems can tell us much that is useful about human communities: about the conditions necessary for the existence of human communities, about the properties human communities 'inherit' because they are special cases of more general kinds of systems, particularly ecosystems.

When I speak about discourse in general, I will usually mean the social activity of making meanings with language and other symbolic systems in some particular kind of situation or setting.