You might be better off trying /r/socialism (they have a number of 101s in their sidebar) /r/Ask_Politics or /r/AskSocialScience for the present state of socialist thought unless your more interested in the history of socialism.

I don't get why so many people think that a socialist government with a capitalist economy is a horrible idea as it seems to be working well with many Nordic countries (i.e. Sweden, Norway, Finland). How do you think this system will work with modern America?

This sub is fine for defining terms and providing a history of political thought and implementation, but be aware that this isn't a "discussion forum", since it does not permit unsubstantiated opinion or speculation. So, this isn't the sub for kicking around ideas of how it could be applied in the USA