How skill rarity works on SkillCraft

Every skill on SkillCraft has a rarity tier. Common, Rare, Epic, Legendary. The tiers aren't set by the author; they're calculated from what people actually do with the skill.

I borrowed the mechanic from collectible card games and old MMO loot tables. The idea: a skill's rarity should tell you something real about how useful it is, not how confidently the author named it.

The formula

Every skill has a popularity score:

score = downloads + (upvotes × 3)

Upvotes count triple because an upvote is a deliberate signal. Somebody tried the skill, used it, and decided it was worth recommending. A download just means curiosity. Both matter, but the weighting keeps real workhorses above skills with catchy titles.

Why not fixed thresholds

First instinct was "Legendary = 50 downloads, Epic = 30, Rare = 10." I built it that way for an afternoon, then ripped it out.

The problem: when SkillCraft had 14 skills and a small community, nothing would ever be Legendary. The Legendary tier would sit empty for months. Painful.

So rarity is relative instead. Two rules cover it.

The first is guaranteed slots. As long as there is engagement in the system, there is always at least one Legendary, one Epic, and one Rare skill live on the site. Every tier stays populated, even on day one.

The second is percentile caps. Once the library passes 20 skills, only the top 5% can be Legendary, top 15% Epic, and top 40% Rare. Everyone else is Common. Legendary doesn't bloat as the site grows; it always means "top of the class."

The thresholds also scale with active users (downloaders and upvoters in the last 14 days), so a skill needs both relative ranking and absolute engagement to move up. No free rides.

Rarity can change

A skill can climb. A skill can also drop if newer skills overtake it. Removing an upvote shifts things. The leaderboard recalculates on every download and every upvote.

That means Legendary isn't a badge you earn once. It's a seat you hold for as long as you deserve it.

Why gamify it at all

Two reasons.

One: it makes the marketplace readable. You can glance at the homepage and see which skills people have tried and liked, without reading 40 descriptions.

Two: it gives authors a reason to build things that actually work. Common is the default tier, and honestly, most skills live there forever. They're fine, but "fine" doesn't climb. The only way to reach Legendary is to help real people save real time. There is no author-side knob to turn.

Which is the whole point. The rarity system is designed to tell the truth about a skill, not to flatter whoever wrote it.

Full mechanic breakdown is on the rarities page, including the exact percentile math and the guaranteed-slot logic.