Many of today's popular games are about a co-operative experience. Shooters (both third-person and first-person) require at least a moderate amount of teamwork from their players, if those players expect to be successful. Squad-based shooters and tactical shooters require even more coordination and planning from players. Success in these games isn't the work of one person, it is the work of many moving parts reacting to situations as they unfold. Each person brings their own skillset, and each person is required to react dynamically as new needs arise.
MMOs such as World of Warcraft have expended this idea as well. The whole idea of a "raid group" is to design a much larger cooperative team, from a much larger pool of possible players and characters. The nature of an MMO means that your players are more variable in nature, and the characters (with all of the choices for race, class, skills, spells, armor, weapons, items, etc.) are infinitely more variable. But, even with the greater variances, many of these groups run like clockwork as they run through the end-game content over and over.
It may go without saying (and it often does), but it needs to be said - running a successful gaming website requires the same kind of teamwork. And I am lucky to have a great team. Our volunteer staff of Editors/Mods do a great job in the day-to-day running of the site, but I want to take a moment to really thank the Admin Team that works behind the scenes.