(
Glossary)
When you look at a tag's landing page (reached by clicking on the tag's name while you're on the Works list), you can see that tag's subtags. Here are the subtags for
Team:

(Sub tags:
*Team Building
*Team Dynamics
**Team Sex
*Team Bonding
*Team Feels
*Team as Family
**Avengers Family
*Team Fluff)
If you click on (or filter by)
Team, you will get all the works tagged with any of these subtags:
Team Fluff, say, or
Team Bonding. However, if you click on
Team Building, you won't get works tagged only with
Team Feels. So if you really love every aspect of teamy goodness, you'll probably want to choose the metatag
Team, rather than clicking each of the subtags separately.
The tags that are indented extra -
Team Sex and
Avengers Family, are subtags of the tags right above them (
Team Dynamics and
Team As Family).
How about in reverse? When you look at a tag's landing page, you can also see the tag's metatags. Here are the metatags for
Avengers Family:

(Meta tags:
* Team as Family
**Team
**Families of Choice
***Family)
This shows that
Avengers Family is a subtag of
Team as Family, meaning anytime someone filters for or clicks on
Team as Family, if they don't exclude Marvel fandoms, they'll get works tagged
Avengers Family.
In turn,
Team as Family is a subtag of both
Team and
Families of Choice. Works tagged with
Avengers Family and
Team as Family will both show up under the filters of
Team and
Families of Choice. And since
Families of Choice is a subtag of
Family, anyone filtering by (or clicking on)
Family will get everything up the line - except
Team, which isn't directly above it.
Next up, how metatags help consumers!