Welcome to the iTetrinet wiki! I've mostly dedicated it to details in the Tetrinet protocol that should be documented, (or documented better) such as:
[[tetrinet protocol: server-to-client messages]]
[[tetrinet protocol: client-to-server messages]]
[[chat channels]]
[[partyline formatting characters]]
[[new game rules string]]
[[game timers]]
[[field updates]]
[[block types]]
[[special blocks]]
[[adding specials to the field]]
[[classic-style adds]]
[[generating garbage lines]]
[[same-blocks mode]]

This information references the unofficial TetriNET "protocol page":http://www.tetrinet.us/staticpages/index.php?page=tnetproto hosted by "tetrinet.us":http://www.tetrinet.us, the "jetrix":http://jetrix.sourceforge.net/ "developer documentation":http://jetrix.sourceforge.net/dev-guide.php and the "GTetrinet":http://gtetrinet.sourceforge.net/index.html source code.