Re: Dave's point #2.
I ran into my first genuine concern yesterday. I follow the photostream of the Library of Congress. They typically dump a few dozen images on at a time. In the past, anytime I saw new posts from the LoC show up on my recent activity, I would open their photostream and scroll back to the photos from the previous upload. To do this, I used the date uploaded as the indicator. When I tried to do this yesterday, I had no clue where to start browsing the photos. Part of that issue can be blamed on my poor memory though.

I haven't had many other practical issues yet.