As mentioned before transactions on the network makes use of double entry bookkeeping. This ensures an accurate accounting of promises to spend time. A sale of a PoL represents a credit in the account of the seller and a debit in the account of a buyer involved in a transaction. Every member has a ledger that has private and public transactions. Private transactions are invisible to other users when viewing and a members profile data whereas public transactions are viewable. Public transactions serve as a point of advertisement to others as to where and how PoL may be purchased. Private transaction are not seen by any other members than their respective parties, they do contribute market statistics on their underlying PoL's.
From each users ledger we can garner several publicly relevant statistics. The user debt to the network, the users assets on the network, and their equity are publicly visible as a measure of contribution. From too high a debt we can infer that user's time is over leveraged. This suggests they may be unreliable, infirmed/dependant/deceased, or in need of some assistance. From too high an assets we can determine that someone has found a way to consistently produce more value then they are consuming this could suggest they control something that is scarce, possess some invaluable skill or craftsmanship, or are in some way in high demand. This represents opportunity for enterprising solutions to help deliver lower costs goods or leverage skill in the form of training to the raise quality of goods across an industry. As we learn more about what affects these numbers we will be be able to triage the needs in a community and help lower costs and optimize time.