Before a bounty is created it can exist in a draft stage off chain. All saved drafts have their own unique URL's, and can be shared for others to read.
When a bounty is created, the token amount is sent to the contract and stay with the bounty. This is an on chain action. When the bounty is live, it can receive comments and fulfillments.
Fulfillments are on chain submissions for the bounty, and can only be accepted by the owner of the bounty. When a fulfillment is accepted, the payout amount of the bounty is transferred to the fulfiller. A bounty can have multiple fulfillments as long as there are funds left on the bounty.
Reviews are off chain ratings, with or without a descriptive comment, for interactions on a bounty. The fulfiller can review the issuer, and the issuer can review the fulfiller. This interaction is per fulfillment. This means that a single bounty can have several reviews from both issuer and fulfiller(s).