This is an evolving short text drafting the main ideas of the author's ontology, before producing special articles on its various aspects. It suggests that the major ontical levels that can be identified in the world -- forms, matter, life, cognition and culture -- all can be described in terms of informational systems that follow combinatorial rules. The emergence of a major level from previous ones is triggered by the appearance of a new kind of memory (genomes, neural systems, symbolic (...) languages). Indeed, each major levels consists of a class of informed systems, which includes a memory subsystem that informs the core subsystem shaped as a model of its environment, in turn interacting with it through the pragmatic subsystems of sensors and effectors. The main classes of phenomena in the world are shortly described and discussed in such terms. Note: The most updated version of this text can be found at gnoli .eu/ontoinfo . (shrink)