The meme was originally designed as an 'iceberg' to show the depth of content on the internet, for instance, the 'light' web would be at the top, unlisted videos a bit below that, unusual webpages below that, and so on and so forth until you reach the 'dark' web or the Abyss on an Iceberg, below the ice. The tiers represent how either disturbing or difficult to find something is, or how concerning the story behind something is. I think what Jackz is trying to do is show more interesting or more rarefied users or their community footprint further down, but to be honest it's not very easy on one website with specific users. If you're trying to make this a reality @jackzfiml perhaps look into the site's history and prolific figures or forum threads that are disturbing/interesting.
@jackzfiml Makes sense, although people have different opinions on "rare" usernames. Some only count the ones that are invalid, and some also count the ones that are not invalid that are a popular word (e.g. Meme).
Also, usernames that only have 3 characters or less are not the only type of accounts that are invalid. There's also the accounts that are a banned word and the ones that exceed 21 characters.