When you feel bonded with a team, a part of your self-identity has merged with the collective identity of the team. The process of losing a little bit of your individuality and taking on a bit of the group identity is what underlies the passionate reactions of sports-team fans. When you join a team and feel bonded to it, you care about the fortunes of the group, because your own fortune is tied up with it and you have an emotional connection with the group that matters to you.
In a virtual team, the fact that you don’t meet in person means you have to make more conscious effort to facilitate the process of creating a team identity and encouraging people to bond with it. You have to make those emotional connections via technology or phone calls, often at strange hours.
When a team has a strong bond they have a bias towards members of their own team; an “us” vs “them” mindset. The team is “us” (the in-group) and the team members are clear about “them” (the out-group). At one level, this bias has a healthy effect of keeping members of the team bonded together and loyal. A too strong “us vs them” bias spawns conflict, stereotyping of out-groups, silos and an inability to collaborate in a multi-team system.