This article addresses how to improve the automated accessibility and visibility of information from Web Information Portals and in particular virtual library systems. Information from web information portals could provide great value to satisfy information needs. But most of this information stays hidden in data silos which are part of that section of the web that is not indexable by common search engines and is therefore called Deep Web. Shared vocabularies like Schema.org helped to increase machine readability of structured information on the web in general, but markup vocabularies didn’t increase the accessibility and visibility of information from data silos. This article addresses the limitations regarding the accessibility of information from data silos on the Deep Web and proposes an extension to Schema.org to fill the identified gaps. The extension improves the automated accessibility and visibility of information provided in web information portals by providing Dynamic Deep Linking capabilities to Deep Web data silos by lifting web forms of web information portals to the level of machine understandable semantic Web Query Interfaces.