One of the very important components of User Experience is Information Architecture. Card Sorting is one of the most popular techniques to get it right. There are quite a few online tools available, but I still prefer the good old offline methods with real paper cards or post-it notes.
Types of Card Sorting:
Basic Card Sorting is the one I like to start with. The idea is to gather a few representatives of your target audience and give them a stack of cards (one card for each piece of information your product is going to offer), so they can sort all the cards into several piles, then they should name the piles, the way they think will be more descriptive for the cards that are located in each group. Another option is to offer users a pre-set “categories” names, but I prefer giving them the freedom, as sometimes it can give valuable ideas.
Reversed Card Sorting, on the opposite, is when you have existing categories with cards in them and you ask users to re-arrange the cards among existing categories, as how they feel is right.
You can offer full freedom to the tested users when they can create their own categories (Open Card Sorting), or just use the fixed categories (Closed Card Sorting). Sometimes, I want to see what category names users can come up with, however, I see better results when there is a limitation in place, proving my belief, that constraints are very good, for everybody =)
That said, I agree that this method may have its flaws (→) (if not used properly). In this article, the author seems to have a wrong impression of the goal which card sorting can help you to achieve. The main idea he is pushing is that card sorting limits you to choose only one single way of presenting the information. I fully support his concerns that different types of users will be likely to expect information to accessible through different paths. However, I don’t think that using card sorting forces you to divide all information following only one path. I believe this technique is just a tool that helps you get an understanding of where the target user expects to see what information. The more users you test it with, the more possible navigation paths you can discover. As a UX designer, you should treat all received insights as food for thought, and make sure all information is accessible through those different paths.