Crowd Mania is all about bringing people together.You start out as a single person running around city and looking for other people to join you.
To add new member in your group, you need to approach a random pedestrian of a neutral color.The more people you run into, the bigger your crowd becomes, but you should always be aware of other players: if their group has more members, yours will be consumed completely and you will have to start from scratch. The good news is, you can do the same as long as you outnumber the opponent.