[spoon]

I think it was about trading colony tech and population with other players. It's one of those things that is so important to do in a competitive game, that if you don't do it, and everyone else does, you will likely lose. Viewed as cheeseball by some, and standard operating procedures by others.

I tend to play in games with Trading prohibited entirely, in part because this aspect introduces a big luck factor (ie, starting next to willing empires that have different colony tech than you is a huge bonus).

Mods have addressed this in a couple of ways: Make colony types a Racial Trait (so it can't be traded) or reduce the research cost of the colony tech (so it isn't such a big deal if they are traded). (though this doesn't address the pop-trading at all).

And you can always play with the Colonize Homeworld Planet Types Only setting.