Amazon is a big place and I can't speak for all of it, but while IT announced that slack was "available" a few months ago, I don't personally know anyone that has actually switched to using it. Everyone still uses Chime.
That may just be a peculiarity of my department, but saying "Amazon as a company switched to slack" is definitely overstating what happened.
That may just be a peculiarity of my department, but saying "Amazon as a company switched to slack" is definitely overstating what happened.