An ontological metaphor posits a thing for a process, suggesting or implying that the operational distinctions required to deal with that thing have exact parallels in the ontological distinctions that apply to successfully execute or manipulate the process. Any use of such a metaphor imposes at least a weak ontology, e.g. simply to say such a thing as "steal cable" is to validate the metaphor of term:intellectual property.
 No one is 'neutral'...
According to this theory, to permit even ordinary use of idiom and metaphors that suggest specific actions or inactions, is to advance doctrines, and, unless some reflective process corrects us, degrades into ideology dividing factions.
While some (such as Hobbes - almost uniquely) denied any value for metaphor or rhetoric, language is rife with it and there's no other known way to learn.
Accordingly we all advocate some action or stance at least implicitly through our choice of metaphors. All language is instructional capital insofar as it tells us what things to understand and which processes require us to think as if we were handling that type of thing.
 ...but everyone's a "new troll"
Observations of endless troll war at Wikipedia led to new troll point of view theory under which all users are trolls and all ontological metaphors are questioned, no matter how much the old trolls treasure them - and ultimately to doctrine:troll.
A troll ontology avoids any ontological metaphors that suggest deference to any authority in particular, since such metaphors lead (according to doctrine:troll to conflict). The new troll point of view requires questioning of all use of terms that strongly imply particular power structures. Living ontology compiles many of these observations from wiki troll culture. Some trolls, notably at dkosopedia.com, have explicitly related trolling to the deep framing theory of George Lakoff, which defines politics as usual as a process of replacing one such metaphor with another.
 War on abstract nouns: with us or against us?
The original definition also due to Lakoff and Mark Johnson in Metaphors We Live By distinguished the ontological as the most basic of all conceptual metaphors, with orientational metaphors and structural metaphors as two other typical kinds.
Ontological metaphors in English are well understood and closely examined in linguistics - google records over a thousand references. Some of it has focused on the term 'war on terror' and the use of such an obviously ontology-level metaphor to force actions or to intimidate dissent or other alternatives. Mara Sophia Zanotto's paper on how ontological metaphors create or reinforce ideology examines these issues more generally.
 Not every conceptual metaphor is ontological
To qualify as an ontological metaphor requires positing a thing for a process. Just to suggest directions or analogies to structures is less specific but perhaps more insidious. Lakoff and Johnson differentiated ontological from structural metaphors especially spatial metaphors. See mediawiki gronks for a relatively detailed examination of some of the problems that these cause. Even more problematic according to L & J are conduit metaphors which imply that there are very few, predefined choices; issue/position/argument for instance rigorizes choices into separate finite position statements so as to facilitate decision, but this implies that the matter is actually up for decision or debate by the people involved - see GEVAD.
There are also orientational metaphors which are often examined in green economics, notably the association of growth with indicators like GDP going up as if this was a positive thing for humans, as it would be if for instance crop yields were going up.
While the effects of these can be serious, they are rarely as extreme or easy to track as a genuinely ontological metaphor.