The concept of an ‘information model‘ goes back at least to the 1970s with the growth of digital information and database software to manage structured data. In the 1980s information models became a key tool for organizing and managing documents and unstructured data, and in the 1990s emerged as a critical requirement for complex content management applications. 

“An Information Model provides the framework for organizing your content so that it can be delivered and reused in a variety of innovative ways. Once you have created an Information Model for your content repository, you will be able to label information in ways that will enhance search and retrieval, making it possible for authors and users to find the information resources they need quickly and easily… The Information Model is the ultimate content-management tool.” (The Gilbane Report, Vol 10, Num 1, 2002 , What is an Information Model & Why do You Need One?).

“An information model provides formalism to the description of a problem domain without constraining how that description is mapped to an actual implementation in software. There may be many mappings of the information model. Such mappings are called data models, irrespective of whether they are object models (e.g. using UML), entity relationship models or XML schemas.” (Wikipedia). 

Also see Integration DEFinition for information modeling (IDEF1X)