XP is not merely earned — it is spent. Every substantive action in Ethos requires XP expenditure, creating an economy where participation has cost. This is what prevents Ethos from becoming a system where people accumulate points without contributing meaningfully.
Content and governance
Voting on content, leaving comments, and writing reviews all cost XP. The amounts are calibrated to be meaningful but not prohibitive — small enough that active users can participate freely, large enough to prevent spam.
Participating in slashing disputes costs more, reflecting the seriousness of governance decisions. Users who vote on whether another user should be penalized are spending significant XP to express their judgment. This ensures that governance participation reflects genuine conviction.
Where your spent XP goes
Not all XP distribution comes from the weekly emission pools. When you spend XP on actions like voting, commenting, or reviewing, that XP flows into self-funded pools that are distributed to content creators.
This creates a circular economy: spending XP on engagement funds rewards for those who create valuable content. If many users find a review valuable enough to upvote, the reviewer earns from the accumulated vote costs. Quality surfaces organically through revealed preference — no direct protocol subsidy required.
Invitations
Inviting new users requires substantial XP, but the XP is transferred to the invitee rather than burned. See "How do invitations work with XP?" for more on this.
Why spending matters
The cost of actions is a core design choice. When voting costs nothing, votes become meaningless. When reviews are free, review quality degrades. By requiring XP expenditure, the system ensures that every vote, review, and comment represents a genuine decision — you chose to spend your limited resources on this action because you believed it was worth it.