When you use an answer link the answer in question is highlighted briefly when you visit the link. The highlighting fades to white for the current sites. For example, try this link: FAQ for Stack Exchange sites or this one on SO: https://stackoverflow.com/questions/194812/list-of-freely-available-programming-books/392926#392926.
On Web Apps, unfortunately, because the background color is grayish, the white background after the color animation now makes the answer stand out. Try: Moderator nominations or How do I delete my Facebook account?
It's not very obvious, but it's definitely visible, and definitely a bug.