We use tags in a similar way to categories. If you want to categorize your panos, use tags. For example, if you publish a pano of a church, give it the tag "church". If you have a pano at night, give it the tag "night".
Tags are useful when the title and description DO NOT include some important "category" words that the panorama might fit into. If you already use the word "church" in the title, you don't really need to also give it the tag "church" (but you can, if you want).
Many people think that giving their pano 30 tags is a good thing. Actually, it's bad. It is MUCH better to write a 50 word description than to give a pano 30 tags, because a description is something that people enjoy reading, and search engines also rank natural, original text much better than a list of tags.
To edit tags for your images, go to the image edit screen and click on the Name & Description tag:
Tags should be used to describe what is in the photo. Please use English only.
Example of good tags: day, night, interior, exterior, shop, restaurant, church, nature, people, beach, water, river, sun, snow, castle
As you can see, these are generic terms - similar to "categories".
Here is an example of excessive and bad tags:
2. Too generic, nonsensical tags: new, digital, vision, 360, best, of, lee, club, fu, sad, live, music - these are useless tags. And if there are other panos that should rightfully have these tags, this panorama will make those other panoramas more difficult to find.
Again, if you want all these words to appear by your pano, then you should write a description in natural language. That is FAR FAR more effective and useful for both search engines and humans.