The floating features were some of my favorite questions, but they aren't easy to find. A number of them don't even mention "floating features" in the post and therefore can't be searched for. It would be much easier to find these posts if they were added with the other features in the sidebar and wiki. If they have been replaced by Tuesday Trivia (which is still unclear), they still deserve a space in the "past features" section.
For those who are curious, those features I have been able to find are:
The same goes for AMA's, although I understand there are many more of those. Apparently this already exists!
Previous AMAs are linked to under the current calender of AMAs.
As for why the Floating Features don't have a link on the sidebar... I don't know the answer! But I agree, this should be rectified! We'll see what we can do about it.
My understanding is that all AMA threads have their own section in the wiki -- /r/AskHistorians/wiki/AMA I think is the link?
Edit: I was close. Link. It's in the sidebar too, but you need to hunt for it.
Voila. Added.