This has irked me a bit for a while. Both the confederacy and the dominion never appeared to have a number of worlds that ranges in the hundreds. Both are kind of imperialistic. But from the existance of bountiful in the novel speed of darkness, we learn that even relatively poor groups can settle on a remote planet. But with the human tendency to create creepy cults, shouldn't there be dozens of worlds out there with just a small population on them? And why does neither imperialist faction try to control them?(one trusted guy in a marine suit would have been enough to control bountiful) How many fringe worlds are out there, and how many are being created?
In Starcraft 1 vanilla campain, at the start of Zerg part, it was stated that the Zerg proceded to lay waste to 9 of the 13 Terran worlds. However lore may change.
StarCraft I stated the Confederacy had 13 worlds. Since then the Mar Sara and/or Char articles on starcraft2.com retconned the number to 13 core Confederate worlds. Numerous lore sources have introduced new settled planets. However, many of these planets are only "lightly" settled (eg Bhekar Ro, which only has one town of note).
Just don't forget about all of those big space platforms and stuff like that. My guess is that there's plenty of people living on them, if you look at the solar panels and bio dome-ish structures on them. No idea who they're aligned to, though.
