Selling original fine art work on the New York Art Exchange (nyaxe.com)involves a number of steps designed to make sure that the work is shipped properly by the seller, received satisfactorily by buyer, and the money flow works correctly throughout. We have what is known as an "escrow" system which is designed to protect both the buyer and the seller in the process.
The message box, controllable from your NYAXE dashboard, contains "action items" which are like messages but REQUIRE some sort of action (acknowledge acceptance of a bid, acknowledge the shipment of the work, etc).
The 8 steps in the process are shown in a visual representation that can be found by clicking HERE.
As you can see, there are a number of steps involved. Selling on-demand printed products (such as giclees) or digital products (such as JPEG images) are much more trivial and do not involve an escrow system; they are delivered by a third party, and the seller (typically the artists) has no further obligation. The sale of original work is, by its nature more complex.