Since the release of OS X Lion last July, the appearance and usability of the new scrollbars came under sharp criticism. Apple took a page straight out of the iOS book; a move that didn’t sit right with some OS X old-timers.
Scrollbars are controls that transform user input into vertical or horizontal content movement. They also happen to visually inform users about the position of the visible area and how much of the overall content it represents. In his lengthy Lion review, Siracusa argues that Apple had to sacrifice the convenience of constantly displaying the foregoing visual cues for the sake of simplifying the interface and saving screen real estate.
Like many design decisions, Apple had to make a compromise. Their decision seem to be based on the premise that, in most cases, the scrollbars are not likely to be in the user’s locus of attention1. Using screen real-estate to display non-critical information is nothing short of a hindrance and is against the progressive disclosure principle. The view provides immediate feedback when the user initiates a scroll, giving them thereby the right information at the right time.
Users who relied heavily on scrollbars in Snow Leopard might be disoriented at first, and will need some time to get used to this change. This setback is a small price to pay if you ask me.