What are Tags with Spaces?
Tags with spaces are tags that can have space characters ( ) in them.
The concept contrasts with hashtags, which can't have spaces in them [why?].
Which Social Media Supports Tags with Spaces?
To my knowledge, only Tumblr supports tags with spaces.
Social media that DON'T support tags with spaces but support hashtags includes Instagram, TikTok, Twitter, Bluesky, Mastodon, and Threads.
Youtube supports both tags with spaces AND hashtags. However, the tags with spaces don't seem to show up anywhere, so I think it may be an old, forgotten feature, from the pre-hashtag Youtube days.
Pinterest also supports tags with spaces, although it calls them "topics," but they also don't seem to appear anywhere, so you can't really filter by tag.
Reddit doesn't support tags at all.