Here are the meanings of some short forms I like to use:
DNW: Die Neue Welt, the german name for the The New World Expansion; the last “big” Expansion Pack for Settlers IV, never released in English.
CP: Community Pack (aka Große Feldzüge in German). The last official Expansion Pack for The Settlers IV. Never included (to my knowledge) in any Gold Edition or Compilation, and fairly obscure even in Germany. It basically consists of a Compilation of fanmade maps based on famous historical battles. It was released shortly before Settlers V, and fixes a problem with the Trojan’s music tracks.
GE: Gold Edition, the regular Gold Edition, or simply the English Version of Settlers IV. Includes everything released internationally (everything up to, not including, the afore mentioned expansions).
GE+: Gold Edition Plus, a second german Gold Edition which features the DNW expansion pack, but still lacks the Community Pack EP. Harder to track down because the box simply reads Gold Edition.
PE: Platinum Edition (Platin Edition in German). Refers to a german-only compilation of Settlers I to IV. Includes the GE and DNW (separately), and may behave a little differently from other versions from time to time.
GOG’s: Refers to GOG.com’s Digital Release, which was released Midsummer 2013. It differs from other versions the most, and offers a slightly better compatibility with modern computers straight away.