First off, welcome
As for the Metaverse, no it is not for multiplayer playing. Gal Civ 2/DA does not have this option. However, what the Metaverse does is that it takes your scores from games you submit to it and then it ranks you amongst others who have also done the same. Its gives you medals for acomplishments and other rewards. By joining the Meta you could also join Empires, which are groups of players who submit games that are then added together into a whole sum(or close to that, i think only a certain precentage goes to the Empire) and then ranks it amongts other Empires.
If you want to find out more about Gal Civ 2 in general go to The Galactic Core at :
http://www.thegalacticcore.com/forum/portal.php
GalCiv2 Forums