If you have many dreams you may want to categorize them. For this you can use tags.
Most dream themes are highly personal, so you want to create your own tags. To do so, you have to go to the Tags page, which shows up in the menu at your personal dream journal.
Once you've created your own tags, they will show up on your dream form.
Available tags will be displayed on all pages within your personal dream journal. Click on them to see all dreams that have been tagged.
Additionally you can see counts for dreams per tag at the research page. The kind of counts and statistics you will see may depend on your account level.