I'm wondering why hostnames ended up being reversed. Ex: .com.example is now example.com.

I recall reading that the reversal happened somewhere during the development of a messaging protocol for ARPANET. com.example@user was reversed to user@example.com and then it just sort of stuck. Am I far off?

Does anyone have any resources or anecdotes that explain this at all? I think I may have even seen this explained in an HN thread once but was unsuccessful in finding it.

Thanks.