Hi,
Once an order in WebStore is placed and paid for things move from the ws_Cart, ws_CartOffer, ws_CartOrderInfo into ws_Order, ws_OrderOffers, ws_OrderOfferProduct tables and the previous rows in the cart tables are removed.
Also now in svn, order information is pushed into reporting tables and reports are available under Administration Menu > Commerce Reports. vThe same data populates the user order history in the profile/my account page.
Hope it helps,
Joe