Everyone has a desire to go out and do some discovery and discover new things. This is an important element to human life, the ability to uncover secrets and find out new information. And because this is so important in life, it must therefore be important in dreams too.
If you have a dream in which you make an important discovery but all you remember is just the act of discovering and not what you were actually trying to discover then this means that you have learned something new and potentially earth shattering in the real world. If the thing that you learned was extremely important and it was very complex then this is even more reason why it would not show up in your dreams and why it would be so complex. If you have a dream in which you make this discovery it basically stands as a representation of the importance of the discovery that you made previously in your dreams.
Sometimes the discovery can be something more conventional and it will show up as a representation of something that you are already clearly familiar with. You already know what's going on with what you're working within the dream and you no longer have to worry about making sure that other people know what you're talking about. The dream itself shows you what that discovery you made is just in case you weren't already aware of it or it didn't seem as obvious to you at first. This is the great thing about having a dream about a discovery, it will be what you want it to be and it will give you all of the necessary information to help you come to a satisfactory conclusion.