# Why So Serious? (The Dark Knight ARG)

> 42 Entertainment claimed over 11 million participants in its Dark Knight ARG.

- Owner: Warner Bros. (studio); 42 Entertainment (agency)
- Kind: Campaign
- Sector: Entertainment
- Seed date: May 2007
- Milestone date: 2008-07-10
- Date basis: Documented milestone; not a measured attention peak. Dates use the stated precision; chart positions are date anchors.
- Spread Score: 32 (Niche, provisional), v1.3
- Mechanics: Mystery & lore, Fandom mobilisation, Real-world spectacle, Platform jump, Press loop

## Summary

Warner Bros. and 42 Entertainment began the ARG in May 2007. Fans unlocked images, solved street hunts and campaigned for Harvey Dent. The agency claims over 11 million participants. The film’s record opening was a wider commercial outcome, not an attributable ARG return.

## Timeline

- May 2007 — Warner Bros. / 42 Entertainment (Open web) — Harvey Dent election billboards and a fictional campaign website appeared in May.
- 2007-05-19 — /Film (Press) — /Film reported that comic-shop Joker cards led fans to an email puzzle revealing Ledger's Joker portrait.
- 2007-05-22 — WIRED (Press) — WIRED identified 42 Entertainment as the agency behind the Joker reveal and its unresolved clues.

The full timeline, metrics and sources are on the case page, or via the Pro API (https://howitspread.com/developers).

Canonical URL: https://howitspread.com/cases/why-so-serious-dark-knight

Cite as: How It Spread (2026). “Why So Serious? (The Dark Knight ARG).” Case HIS-01441. Spread Score v1.3: 32/100. Updated 2026-10-23. https://howitspread.com/id/HIS-01441