The Lean Startup: How Today's Entrepreneurs Use Continuous Innovation to Create Radically Successful Businesses · chapter 6 · id the-lean-startup-c6-01-drew-houston-validated-dropbox
“Drew Houston validated Dropbox demand by creating a simple demo video. The beta waitlist jumped from 5,000 to 75,000 signups overnight -- proof that an MVP can validate a market before building the full product.”
TRUE, BUTconfidence: high⚠ extracted by pipeline, re-audit pending
Receipts
Drew Houston, MIT Commencement Speech (2013)source alive
Houston himself has consistently cited the 5,000 to 75,000 figure in multiple talks including MIT commencement (2013) and Startup Lessons Learned (2010).
TechCrunch -- Dropbox Emerges from Stealth (Sept 2008)FLAGGED: dead link (404)
Dropbox launched its public beta in September 2008 after being in private beta for months with a working product and $1.2M in seed funding from Y Combinator and Sequoia.
Y Combinator -- Dropbox profilesource alive
Dropbox was part of YC S07 batch. By the time of the viral video (Sept 2008), the company had been building for over a year with seed funding.
This claim is a stable, citable object. If you can falsify a verdict, tell us. Corrections are loud here.