tabs now replace the title bar. AFAIK this feature first appeared in Google Chrome. It seems a sensible use of vertical space.

OTOH I find it a bit annoying occasionally that I can't see the, well, title of a website.

The top sites page makes is effectively an adaptive bookmarks page, showing thumbs of the dozen sites Safari thinks you visit most often.

Presumably from Chrome, too; at least, that's where I first saw that feature.