Google URL Shortener - After shortening a link the shortened link is automatically selected.
Google+ - Sending feedback in Google+ gives you the option to highlight the problem and blackout personal stuff.
/via Robert Winters
Google Translate - Hovering over the translation, highlights the matching phrase in the original text. Clicking on it reveals alternate translations.
/via Shruti Ramiah
Chrome - When using the search box on the preferences page it highlights the results with a yellow notification.
Alfred - Highlights the keyboard-shortcut when you disable all other GUI to access the preferences.
/via Hans Petter Eikemo
Chrome - When a tab in Chrome has updated content, a light gradient moves from right to left on the tab. Keep your eye on the upper left of the video.
/via Tim Banks
Apple - Signup form shows a lighter version of input description once you clicked on. Then once deselected the blue border subtly fades out.
New York Times - Interesting interaction design around hyperlinking/highlighting paragraphs and sentences. Read more here