For the person that asked about bookmarking -
If you are on a computer, hover over the post you want to bookmark, and a box that says "Bookmark" will appear. Click on it, and it will show "Saving" and then "Saved".
If you are on the mobile site (not the app) the "Bookmark" box is at the bottom of each post.
I'm not sure if you can bookmark on the app.
What happens is that the next time you open the thread, it jumps straight to the bookmark. However, the bookmark does seem to disappear if you move backwards in the thread (to check previous pages).
It means you don't have to find something witty to say everytime you want to mark your place!