As early as St. Paul, the battle between identities or singularities has been waged. Paul was one of the first to articulate the wiping away of identities (no male/female, slave/free, and Gentile/Jew) for a new community. Early Christian thought always had a communal outlook and basis. Unfortunately, history shows those Christian strands of communities that remained faithful to Paul's ideas to have either been so minor a population as to be ignored or to be totally persecuted. For example, a lot that we know about the 15th century peaceful Anabaptists is written by those that mercilessly persecuted them.
One of the problems brought by the rise of the nation-state and modernity, was of the totality of the so-called organic community. This organic community does away with the real differences that make up the nation but also each person. Translation: These people are the real German "essence" and those are not.
From reading both Negri and Deleuze, one can see how a human person is a singularity in that he/she is made up of a lot more things than simple autonomous, rational thinking subjects. We are interconnected with other singularities. For Negri, this plays out in the way we deal with what he calls the common. Great quote by Negri: "Common is that which enriches the productivity of singularities! Common is the fact that a lot of ideas come to me when you and I talk about something! Common is the fact that if I love you, we invent things together!"