One of the new features of MovableType 3.31 is Tag. I still use the old template files. I don’t know if the new template includes it or not.
The tag is good facility to organize post by tag word. You can also know which tag word is mentioned most often.
Let me DIY my templates.
1) Add a module, Tag Cloud.
2) Add following code into the sidebar or someplace you like.
<$MTInclude module="Tag cloud" $>
3) If you want Tag displayed in the Individual Entry Archive, add following code into this template.
The entry "<$MTEntryTitle$>" is tagged:
<MTEntryTags glue=", "><$MTTagName$></MTEntryTags>
Rebuild relative files, all done.
Now, when you add a new post with Tags, the tag cloud and tagged words will be shown in the right place.