Google+ needs some mechanism for me to create chains of discussion that allows me to indicate my 1/2 hour rant didn't take into account everyone else's very valid points that were made in the mean time.
Yeah, much of the interface is...clunky. For instance, this message came with a notification, but after reading it I don't find it on my page or on yours, and I have to go back to notifications, where it has disappeared, and read the previously read notifications. The Facebook message model is much, much better for correspondence.
Now it shows up on your page. And the hangouts/messaging sidebar is a mess as well. You can have a notification there for months and not notice it. I imagine there might be preferences, but the default should be a bit better, methinks. Everything is sprayed out all over the place. How will we keep track of or even remember this message thread in the future since there's no place to store it other than among the flow of posts? We won't.
