@chrishoward yes, this is at great way to do tags. The number of tags could be virtually unlimited. I’m not sure what you would do with an array of tags though, since you wouldn’t be able display them in a component. You can however display the relation as a list of tags, then click into the tag where you can then further use relations an lookups to find other people or items with the same tag.
I think the ability to combine relation and lookup columns to get an array of values is one of the most powerful features of glide that I think many people don’t realize they can do. Also being able to use an array of values for many to many relations. You can use an array on either side of a relation column. One thing I like to play with, is using relation/lookup/relation combinations.