I've seen these cool groups of words on other photo sites. What's that?

It's called a tag cloud. Your tag cloud will be created for you as soon as you upload a photo and give it a tag. A tag is a keyword that represents the photo. A pet's tag could be cat, animals, furry. When you add tags, don't use commas. Only use spaces in between. If you can't find what you're looking for you can search the site.