These numbers represent the number of Shipments and the amount of Revenue processed through the trade assurance program.
They are the exact numbers that have been reported through Alibaba. (some sales are made off Alibaba so their revenues and orders may be larger)
As a seller you should consider these numbers when you are looking for a supplier and find a supplier that is right for your needs.
Suppliers with High Order Numbers and Revenue
More experience, Larger capacity, Proven track record, custom tooling more likely available
Larger Customers than you that will take priority in busy periods
Suppliers with Low Order Number and Revenue
More likely to foster relationship and work with you to create a custom product, your orders will be highest priority
Potentially outgrow their capacity, smaller proven track record, less experience, less tooling available
All of these points are general rules of thumb, each supplier is different and you should base your selection on a lot more factors like communication, sample quality location etc