iFarted/memory-bank/research/yo-app.md

Research Notes — "Yo!" (2014) and What We Copy for iFarted

Researched 2026-09-09. Sources: Wikipedia "Yo (app)" (current revision, 2026) + CNET article "The million-dollar app that exists to say 'Yo'" (June 19, 2014), retrieved via Wayback Machine.

What Yo was

• iOS/Android/Windows Phone app released April 1, 2014 by Israeli developer Or Arbel, built in ~8 hours at the request of Moshe Hogeg (Mobli CEO), who wanted a single-button app to "call" his assistant/wife without picking up the phone.
• Apple initially rejected it for being "too simple." It exploded after appearing on Product Hunt. ~20k users in month one; 1M+ downloads by June 2014; 100M+ "Yos" sent by Sept 2014; ~$2.5M raised at a $5–10M valuation.
• Company shut down in 2016 ("autopilot"); later kept alive via Patreon (2018). It never had a real business model — the cautionary tale for our ad + IAP plan.

How it worked (verified quotes)

• Wikipedia's feature summary is almost word-for-word our user's brief: "The app enabled users to send individual notifications to other users, simply containing the word 'Yo'. Users could additionally send their location."
• Sending (CNET): "You have a list of contacts. You tap one of those contacts, and they receive a notification saying simply, 'Yo', along with an audio alert of the word being spoken."
• Positioning (Arbel via NYT/CNET): "We like to call it context-based messaging. You understand by the context what is being said." The same "Yo" means good morning, "thinking about you", "meeting's over", "are you up?" depending on context.
• Addressing was by unique username — e.g., a "worldcup" account yo'd followers whenever a team scored (later formalized via a public Yo API).
• Evolution: Aug 2014 → profiles, links, hashtags. Oct 2014 → send your location. June 2015 v2 → photos or location "within 1 swipe and a tap from the home screen" + groups (yo several friends with one tap).
• Notifications were text + audio (the word spoken aloud). No inbox/feed of messages — the notification was the message.

Failures / lessons (what NOT to repeat)

1. No monetization → died. We monetize from day one: ads + one-time Remove Ads IAP.
2. June 2014 security hack (Isaiah Turner): anyone could retrieve any user's phone number and spam/spoof Yos → we must: auth on every endpoint, never leak PII from unauthenticated lookups, unguessable tokens, per-sender rate limits, block path, abuse monitoring.
3. Apple review rejected "too simple" → prepare a purpose/value explanation for App Review using the context-based messaging framing.
4. Novelty decays fast → single-purpose is the hook; retention levers are the friend-connection flow and monetization, not features.

What we adopt ("do that")

Yo	iFarted adaptation
Single fixed word "Yo", zero typing	Single fixed phrase "I farted.", zero typing
Push = "Yo" + audio alert	Push body "I farted." (+ sender display name); custom audio notification sound (iOS bundle sound <30s; Android notification-channel sound)
Contact list, tap to send	Home = recipient list, tap → send; one-tap "fart back" after receiving
Context-based messaging	Same framing: one phrase, meaning comes from context
Username addressing	All three connection methods: username search · phone contacts (opt-in) · invite code/link
Location attach (Oct 2014)	Per-message location toggle → map pin when recipient opens
Groups (v2, 2015)	Post-MVP stretch feature
No revenue model	AdMob ads + non-consumable Remove Ads IAP

Copy/UX defaults derived from Yo (pending final wording)

• Notification: title = sender's display name, body = "I farted."
• Home: recipient list (recent first), big primary send action; empty state nudges "Add friends".
• No message history/inbox — messages are the notifications themselves (ephemeral).
• Primary onboarding: claim a unique @username; optionally verify phone for contact matching; invite via code/link.