The second point is really interesting - how instrumental was having a semi-public feed in them taking off? I use venmo b/c everyone I know has it, it has my bank info anyways, and it's easy to find people. Even now with a gazillion options I still default to venmo.

On the latter point of finding people though, a public feed has been useful. Often when I venmo someone new (ex. dinner), it's helpful to see my friends also having venmo'ed the person so I know I have the right account.