Yes, I am a big fan of SEGA myself, but this has bugged me recently. Why is Dr. Robotnik now referred to as Dr. Eggman? I understand he looks like an egg, but did SEGA change his name? Or is that some bad new marketing?
I know that "Dr. Robotnik" is in fact the american name for his japanese counter-part, "Eggman", but I don't understand the "now referred to as Dr. Eggman". In which US Sonic games is he called Eggman?
I think "Eggman" was Robotnik's nickname in the Japanese Sonics for a long time before the Adventure series, so eventually SEGA/Sonic Team figured it may as well be his "normal" name in the US/European versions too. His "official" name is still Dr. Ivo Robotnik, though.
The Sonic Adventure games don't continue the plotline of the Genesis and Saturn titles, either - for one, the SA games are set on Earth, as opposed to the old Sonics taking place on Mobius' islands (Floating Island, Angel Island, South Island, etc.) Sonic Heroes seems to be set in Mobius as well, but it has its own separate "timeline" to avoid creating even more plotholes. Apparently Knuckles needs another excuse to let Eggman steal the Master/Chaos Emeralds for the umpteenth time. <_<
I suggest visiting the South Island Forums for plot info, Chaos (Emerald) Theory, and other miscellaneous discussion.