I've been trying to understand this for about a year, it's from Using_Custom_Fields:
To add your "Today's Mood", repeat the process and add "Today's Mood" to the key and a description of your mood in the value text boxes and click Add Custom Field to save this information with the post.
On your next post, you can add a new book and mood to your meta-data. In the Custom Fields section, the Key will now feature a pull down list with the previously entered Custom Fields. Choose "Currently Reading" and then enter the new book you are reading in the value. Click Add Custom Field and then repeat the process to add "Today's Mood".
You only need to create a new "KEY" once, after which you can assign a value to that key for every post, if you so desire. You can also assign more than one Value to a key, for a post. This will come in handy for people who read more than one book at a time.
I don't see anything in the custom feild interface called a "key" I only see "name" and "value". And I'm really confused with the reference to meta data, I thought that was the info which appears above posts about author and date and category? huh?
I've tried to add custom feilds to posts but nothing happens. Part of the problem is I'm not really sure what one is, although I think I know, but no way to test since I can't make any progress on it.
if anyone may be able to provide some basics that could help me understand what custom feilds are and how to make one it would be quite liberating. It's embarrassing, I've done so much custom stuff with WP but I'm a complete noob on this.
