What is the difference between a section and a category?

Sections feature security, overlays and rendering styles.

Simple blogging tools are able to classify posts into several categories, and YACS has this feature as well.

[title]What are categories used for?[/title] YACS categories allow you:
* to group together any set of pages
* to archive pages by weeks and by months (done automatically on article publication)
* to structure concepts into a categories tree, with sub-categories, etc.
* to add rendering steps to some pages (eg., the Featured category, to list some articles at the site home page)

[title]What are sections used for?[/title] At the same time, YACS also features sections. Actually, every article posted to a YACS site has to be anchored to exactly one section. Does it mean that sections are some sort of "super-categories"? Well, this may happen in some cases. But sections also have very specific attributes that categories do not have.
Access restrictions - Some sections are public, while others are reserved to authenticated members or only to associates. Of course, YACS ensures that access rules are cascaded to anchored articles. Create protected sections each time you want to restrict access to some information.
Overlay extension - Articles can be extended using the overlay interface. You just have to edit a section and to mention, in the overlay field, the name of the PHP class to use. For example, drop 'recipe' to transform a section to a cookbook, or 'poll' to create a section dedicated to polls. Of course, you can create overlays of your own.
Skin variant - While this has not been demonstrated yet, you can implement some skin variation for one section. Actually you can even select a specific skin for any section. Basically, this gives you the power of selecting quite rich rendering options for your site. For example, you can select one blog style for section A, and another blog style for section B. If you have a single skin, and want to transmit the variant you want to use, add the 'variant_XXXX' to the options field, where XXXX is your actual option. If you prefer to use a particular skin at some section, use 'skin_YYYY' instead, where YYYY is the name of the target skin.