As a junior i often wrote "Hi, do you have a moment? (ok if not)" in slack (or lync at the time) to senior people when I had questions. I then didn't expect a reply unless the senior person was not busy or bored. If no reply within 5 mins I would ask the next person.
I did this when I had a question that perhaps 20 people who I knew could answer, though I had no way of telling who (if anyone) was free to chat something over with me. I didn't send a group email as the projects that I was working on contained need to know stuff, so sending details of it to 20 people would be a no-go but saying I spoke about this with Bob, here is the audit trail would be fine.
I still think that this was optimal in that situation, though I often see it derided with no better option suggested.
I did this when I had a question that perhaps 20 people who I knew could answer, though I had no way of telling who (if anyone) was free to chat something over with me. I didn't send a group email as the projects that I was working on contained need to know stuff, so sending details of it to 20 people would be a no-go but saying I spoke about this with Bob, here is the audit trail would be fine.
I still think that this was optimal in that situation, though I often see it derided with no better option suggested.