A system and method for providing virtual items to users of an online game operated in a virtual space. Multiple users may participate in affiliations or alliances of discrete groups of users in an online game and may access the online game through client computing platforms associated with the users. The affiliations may have affiliation game units associated with affiliations which provide a benefit to the members of the online game. Affiliation members may cumulatively obtain affiliation game units and/or upgrade affiliation game units by providing one or more virtual items. Upgrading affiliation game units may require the cooperation of multiple members of the affiliation.