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This design's homepage is centered around a large searchbar which suggests tutorials as key words are typed in, making it extremely efficient. A selection of commonly viewed tutorials is also available below the search bar for even quicker access. The tutorial view itself is structured so you can see at a glance how much more there is to the tutorial and skip around very easily. While a moderately skilled user could learn this interface easily, it probably suffers from usability issues with the unskilled user class because of the computer-intuition required. Anyone who can use a search bar will have an easy time using the home page, at least, but the slide interface of the tutorials, while easy to use, might be offputting to some. The slide model has the property that despite looking daunting at first, it is actually fairly easy to go forwards and backwards. As a result, any misplaced clicks or confused actions are safe and easily recovered from.
S&D 3
Design 3 borrows a bit of appearance from w3schools, which hopefully means that it's usable. It organizes tasks by difficulty, which hopefully makes it efficient and easy to learn. There is also a help feature built into the site to aid new users learn faster. The prereqs listed above each tutorial make it efficient to find other relevant tutorials and figure out if the user knows everything to attempt the current tutorial. There is also a tutorial listing that lets users filter by key factors such as difficulty to find a tutorial even if they can't describe it. We anticipate that this page might present initial difficulties to novices, but that it is actually fairly learnable and will quickly start helping them find tutorials. There is, however, a lot more content on some of the pages here, making it easier for some users to get lost or accidentally click into another section. There is potential for lapses and slips here due the filtering page. For this website, the best safety net is probably the user's browser's back button.