You said you were looking for “when the ideas started gathering people”. I do suspect there’s an interesting counterfactual where in-person gathering wasn’t a major part of the EA movement. I can think of some other movements where in-person gathering is not focal. In any case, I’m not hung up on the distinction, it just seemed worth mentioning.
The first EA summit was the one you linked in summer 2013, so it just wasn’t early enough.
(You could argue that it was important for the movement’s growth)
You said you were looking for “when the ideas started gathering people”. I do suspect there’s an interesting counterfactual where in-person gathering wasn’t a major part of the EA movement. I can think of some other movements where in-person gathering is not focal. In any case, I’m not hung up on the distinction, it just seemed worth mentioning.