If I remember correctly early on there was both the firehose of all tweets you could access and easy to call apis to post tweets. So there were a set of programmatic standards to control how you could communicate, which sounds close enough to me for a blog post.

But only if memory serves correctly, I do not know the timelines off the top of my head.

The Twitter of 2009 was a rather different beast to the Twitter of the 2020s. Open APIs were a big part of it, and the idea that people would upload all sorts of random data into their feeds which others could tap into.

(In practice, it never went much further than running apps, book reviews or calorie counters).

It's pretty inconceivable that he doesn't know what a protocol is. Far more likely is that he is using the term "protocol" with a meaning you either are unable, or refuse, to understand.