The invention is incorporated into an interactive web data seller widget that enables any ecommerce site to provide access to and from large, remotely stored databases to its web visitors and for those visitors to prospect/filter within the databases, for example both via geographic and demographic criteria. Users can find, for example, appropriate geographic and demographic matches to any applicable search criteria. Additionally the invention enables the web visitor to order as a deliverable subset of the remotely stored database a detailed list of the required database subset and for the ecommerce site to sell that data subset to the visitor via a web shopping cart and checkout process. And the invention enables the web visitor to preview the selected subset of data from any database prior to placing an order for the same.