Social Transmission

How value moves from one person to another: shared artefacts, invited people, and permissioned contact bridges. Growth that feels good respects consent at every hop.

Definition

Social transmission is the set of product behaviours that let a user’s outcome or recommendation reach someone else. Three Tools, Techniques, and Practices (TTPs) cover distinct jobs—do not collapse them:

flowchart TB
  User[User with value] --> Share[Shareability — artefact or story]
  User --> Invite[Referral — invite a person]
  User --> Bridge[Contact Bridge — people they know]
  Share --> DL[Deep-link landing]
  Invite --> DL
  Bridge --> PS[Permission Serve]
  PS --> DL
  DL --> Recipient[Recipient in the right moment]

Job	TTP	What moves
Tell the story of a result	Shareability	An artefact, link, or narrative the user owns
Invite someone who would benefit	Referral	A person + a clear, honest path for both sides
Connect to people already known	Contact Bridge	A permissioned people-picker for a user-chosen purpose

Deep-link is the plumbing that lands the recipient in the right moment; Permission Serve is the consent pattern for any sensitive ask (including contacts).

Why it matters

Reflective emotion—pride, belonging, “I look good recommending this”—is what makes people transmit. Pressure, pre-selected contact lists, or bait-and-switch invites convert once and then brand the product as extractive. Discovery maps where people already talk and seek (How Customers Talk, Search, and Buy); this concept is how in-product growth matches those channels without dark patterns.

Deep dive

1. Shareability first. If the outcome is not worth showing, no invite loop will save growth. Design the shareable moment (export, public link, story card) before the referral mechanic.
2. Referral is a dual experience. The inviter needs dignity and control; the invitee needs honesty about what they’re joining and an easy decline. Fake scarcity and guilt copy fail User Agency.
3. Contact Bridge is not growth hacking. Address-book access is a high-trust ask: value must be visible before the prompt, selection must be user-driven, and harvesting contacts for spam is out of scope for this handbook.
4. Transmission inherits trust. Broken deep links, surprise paywalls after a share, or mismatched landing states burn both parties—see Calibrated Trust and Surfaces, Flows, and States.

For engineers and agents

• Model three payloads separately: share artefact (URL, image, file), invite token (attribution + landing intent), contact scope (OS permission + in-app selection). Mixing them produces consent bugs.
• Preserve recipient context: campaign/invite metadata should shape first-run and remain queryable—stripping it at the door discards why they came.
• Audit preselection: any control that defaults “invite all” or “share with followers” without an equal-weight decline is a finding.
• When reviewing Growth strategy work, classify the change as Shareability, Referral, or Contact Bridge before applying that card’s Don’t list.

Where it shows up

• TTPs: Shareability, Referral, Contact Bridge, Deep-link, Permission Serve
• Strategies: Growth & Viral, Engagement
• Concepts: Emotional Design (reflective layer), User Agency, Peak–End Rule (shared peaks)

Further reading

• How Customers Talk, Search, and Buy — Where transmission already happens before your product exists.
• Permission Serve — Consent timing for contacts and other sensitive access.
• Deceptive Patterns: Friend Spam — The anti-pattern Contact Bridge and Referral must never become.