Make no mistake, though: Amaq is putting out the Islamic State’s message, and the veneer of separation between the terrorist group and what has now become its unacknowledged wire service is quickly disintegrating. Though the group is not officially part of the ISIS media apparatus, it functions much that way.

“It has become much more assimilated into the Islamic State’s propaganda infrastructure, and now it’s a fully fledged and very important part of it. It has become the first point of publication for claims of responsibility by the group — though not as a rule,” said Charlie Winter, a senior researcher at the Transcultural Conflict and Violence Initiative at Georgia State. He pointed out that one of the biggest attacks — the Nov. 13 killings in Paris — followed the more traditional route, with the claim of responsibility published directly by ISIS.

The Islamic State maintains its official Al Bayan radio station, which puts out daily news bulletins, and its monthly magazine Dabiq, as well as many production companies that put out its grisly videos. Beyond those, there are also media offices in each of the Islamic State’s provinces. The material that goes out on these official outlets has the ultimate stamp of ISIS approval — that’s what they want us to know about their ideology and their tactics.

Those messages are tightly controlled, honed to both appeal to the largest numbers of recruits as well as designed to intimidate and sow fear.

As one example of how much they control their messaging, consider what happened to the British jihadist Omar Hussain. This month, Mr. Hussain published a string of essays about life under the Islamic State — and then he was served a cease-and-desist order by the ISIS Media Committee.