Safari 6 — After dragging a link to the bookmarks bar, you can immediately change the name of the bookmark.
Safari - When pinning a topsite, the icon of the needle looks like it’s really going in.
Lion Safari - The scrollbar changes the color depending of the background of the current website. (dark or light)
iOS Safari - When you’re typing something followed by a dot in address bar, pressing the .com key, will result in a perfect one-dot spelling anyway. Then when you press it longer it shows you other domain options.
/via Kyle & solonsky
Webkit - When entering text into a password field in WebKit based browsers (f.e. Safari & Chrome), a small icon will appear if caps lock is activated
/via Tobias Michealson