Tags allow for individuals to search for a entry in an easier way. The movabletype blog allows you to build a tag cloud in which you can place on the left or right sides through the design drop down under the heading widgets. remember to add a comma after each tag.
*widgets are special items the movable type recognizes and they do different things.
Keywords allow users to search easier. Keywords is a meta item for your website and helps users find it on google and other queries.
*meta data are information stored on the site for site recognition
You can set the privacy level for your entry, whether it should be public or private (on the right side)
Trackback urls allows a person to use it on their blog to reference yours. if a person does that and their blog system allows for automatic ping backs you will be able to see a count of how many people are trackbacking your entry.
Lastly you can drag this screen to make it larger or smaller for writing prefences.