Hi S Page,
Me too. Likewise the blue background and shape of the current filters looks like a button. What happens if you click it?
Good point, one could think of several actions assigned to them, but none of them would be very discoverable.
* Marking topics with recent activity: the color we're familiar with in this context (from e.g. history pages) is green, not blue.

Yes, when you follow a Permalink to a post in a topic, that post has a green left bar (example). But when you click on a "Hhhippo and 2 others responded" message notification, there's an extra parameter fromnotif=1 that causes Flow to highlight that post and newer ones (example).
Yes, I know those. But what I meant was consistency with mediawiki history pages, not with the current Flow. People are not used to Flow yet, so changing something there should be no problem.
I don't like the two colors, we should pick one and preserve the thick bar for the actual reply and a lighter one for newer posts, there was a bug or Trello card comment about it.
What do you mean by "the actual reply"? Is there a special notification for a direct reply to one of my posts? I'm not sure that makes too much sense at the moment: as long as structured discussions are largely disabled, and many of the reply 'buttons' seem to be functionally equivalent, we can't rely on users pressing the right 'reply', so we're not sure what they're replying to.

I think the width of the bars should be in between those of the two versions we have now, and the same for all types. The position should be like the current permalink ones (the placement of the fromnotif bars looks buggy, at least in FF/MonoBook). In the color scheme I suggested earlier, the 'new activity' bars would be colored depending on the type of activity, and the permalinks blue, since they provide some kind of search result.
(A gadget writer could add a client-side "Highlight newer posts than this" action: fame and fortune awaits)
Yes yes, got the hint already last time ;-)  It's just so much more fun to let other people do the work and then complain about the results... :-)

Seriously, I never did much in JavaScript, and while it would be fun to try, I don't expect to get to it anytime soon. I'm brewing some more ideas on Pau's ToC atm, hope something will hatch the next days.

Best wishes
Hhhippo