Для виндозного сервака, на котором стоит Word
читай VIII. COM support functions for Windows
COM is a technology which allows the reuse of code written in any language (by any language) using a standard calling convention and hiding behind APIs the implementation details such as what machine the Component is stored on and the executable which houses it. It can be thought of as a super Remote Procedure Call (RPC) mechanism with some basic object roots. It separates implementation from interface.
COM encourages versioning, separation of implementation from interface and hiding the implementation details such as executable location and the language it was written in.