There is common factor in what both United Nations and social enterprise pursue as their final goal- “making this world a better place”.
The United Nations consists of 193 countries (in 2011 July) and it is basically funded by the member nations. In other words, all the actions the United Nations is to take must happen under all the counties’ agreement, which restricts the actions taken by the United Nations in terms of time, issues to solve, and so on. It is hard for the United Nations to take part in small social improvement movements that focus on specific area, since it is funded by the member nations, and would rather focus on larger issues happening in today’s world. On the other hand, social enterprise can set a target on such smaller social movements. Moreover, the activities are less restricted since the funder is company itself, and it can do whatever the company believes it is beneficial for the company and the society.
In my personal opinion, Social enterprise exists in order to cover the work that cannot be completed by the United Nations. This does not mean either organization is better or not. The reason why one does not eliminate another is because both exist to pursue the same goal, but resolving the issues by setting different targets and taking different approaches.