I know I've committed to sites where I haven't fulfilled my commitment. Those commitments are no longer active; I've failed them.
How and where can I see what these commitments were?
You can go to your profile page. It will list the proposals that you follow. There are also two helpful sections:
Commitments that you have fulfilled.
These are commitments that are still pending. You can commit to three proposals at a time. Proposals with a green box are still in the commitment phase, and blue box proposals are in beta. All these commitments are unfulfilled.