As an administrator, you have to use the Administrator tool to add your user's profile to the pipeline workspaces for all the other users. After this action you will be able to see all opportunities from the pipeline view of the Web interface.
To do this:
1. Right click on an Org in the admin tool that has the User's pipeline you would like to be added to and select "Show content"
2. Click on the pipeline you would like to be added to and click the "Membership" button at the bottom of the dialog
3. Find your user in the user list on the left and click on the arrow pointing right to add your user into the members list.
4. Click OK