Atari Wiki talk:General disclaimer
http://www.texttaougetchi.com hardware section would be good. 1 Subsection dealing with addons such as harddrives etc
No need to rewrite all mods out there, but a section with general info about them would be nice I think. And also a subsection with in-depth information about the technical aspects of the ST, how the GLUE/MMU/DMA/Shifter works etc. Basically info needed to design an VHDL model of an Atari.