On the frontpage, the entire card for a stream should be clickable, not just the headline. Same goes for the dropdown to switch to a private group (btw, if the name of a group is too long, it messes up the header bar).
Having private groups could prove to be pretty useful. Switching seems simple enough. Do I see somewhere which thoughtstream belong to this group? Are all displayed streams part of this group and everything filtered out? I think that's it