CCK stands for Content Construction Kit. CCK's allow you to define the structure of the content. For instance, in Joomla, we have articles (which consist of title, author, text, etc.) and web links (title, URL, description). Those are two different types of content with different bits of information.
With a CCK you can define as many content types as you want. Need a Product (catalog number, description, specs, picture, price)? Want your authors to submit articles the same way (title, intro, picture, full text, geographic location, date)? With K2 you can do that.
In K2, the basic article (called an item) is divided into different tabs: Content, Image, Image Gallery, Video, Extra Fields, and Attachments.
Content
This is the basic information such as Title, Intro & Full Text, Category, Tags and Meta information.You can use the Tags as a workaround to show a single article in multiple places.
Image
Here you can enter a single image. Having the image separated out instead of uploaded directly into the article (which you could do as well) means that you can style it consistently.
Image Gallery
For when you have a gallery to present. Requires that you have the newest version of Simple Gallery installed. Currently only the Pro version has been updated to 2.0, but the free version is due out any time now.
Video
For uniform presentation of video. Requires that you have AllVideos installed.
Extra Fields
This is the fun part. Here's where you can set up all the specific information that you need for this type of content. You create the fields then group them together. When you create a Category you specify which group of Extra Fields you want to include. You can reuse these fields and groups.
Attachments
For easy and uniform presentation of attachments.
K2 comes with a style sheet that you can inactivate if you want. I would have preferred to be able to point to a specific style sheet. I don't want to bring in all these styles for all my pages, but I'd like to be able to change a few things without worrying about them being wiped out. I've decided to leave the styling as is while the product is still in beta.
The JCE editor was throwing errors, but when I switched back to TINY, it worked fine. Update: When I upgraded JCE from 1.5.1 to 1.5.2 the errors went away.
K2 is still in beta and it still has some issues which are being worked on. See the forum at Joomlaworks to judge the progress.
