I'm using "tree view", and it appears that posts work more-or-less the way you want, expanding and collapsing. Â I'm also using Chrome as my browser for this, since it's a Google site. Â Not sure how IE or Firefox will handle it. Â (I've learned that when operating Microsoft based websites, like Outlook Web Access (for work email) or Sharepoint, that it works best if you use Microsoft IE for those. Â I'd hope Google isn't as evil as MS (it's in their mission statement, after all), but as long as I've got it....
One thing I do, when I see that there is a new post (marked by a number after the "Philosophy and ...." in the left pane) Â is I click on that, which shows me all the categories. Â Then I click on "Show all topics" on the upper right. Â Now I can see where the new message is hiding.
As the list of posts becomes long, it may be necessary to apply filters (top middle button) to weed out the older threads. Â Of course, the filters settings don't seem to be a savable feature.
I agree that it's not intuitive, nor as powerful as one could hope.
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