An opportunity is someone you have located through a search in the App that you would like to bookmark but maybe are not quite ready to connect with. It is like saving a business card for future reference. When you add someone to your opportunities list, you have limited networking options and that person does not know that you have saved their Calling Card. You are however, able to message that person and make personal notes about them. When you are ready invite them to join your Network!
When you want to look up who you have in your Opportunities list just tap the far upper left icon for the menu. Select Opportunities and your list will appear.