# Free-text signup attribution for dark funnel discovery

> Add a free-text 'How did you hear about us?' field during signup instead of a dropdown to uncover the untraceable channels driving 30-50% of B2B signups.

- Canonical HTML: https://growth.iangoh.com/growth-ideas/free-text-signup-attribution-for-dark-funnel-discovery/
- Source: [postiv.ai](https://postiv.ai/blog/saas-growth-hacking)
- GrowthDex source hub: [postiv.ai](/sources/postiv-ai-postiv-ai/)
- Last checked: March 23, 2026
- Rarity: epic
- Budget: free
- Channels: Communities, Referrals
- Stages: 0-100, 100-1K
- Key metric: 50% of signups came from private Slack chan

## Why this can grow

Traditional analytics attributes most dark funnel traffic as 'Direct' or 'Organic,' hiding the real channels that drive trust and buying decisions. A free-text field captures the actual discovery path in the user's own words, revealing channels like private communities, personal recommendations, and podcast mentions that you'd otherwise never invest in. Founders who discover these hidden channels can double down on fueling word-of-mouth instead of over-investing in trackable but lower-trust paid channels.

## Ian's take

From scaling consumer platforms across MENA and Southeast Asia, my default is to distrust growth work that only looks good in a slide. I would treat this as earning the right to be in the room, not dropping a campaign into a room. In community-led growth, the first job is to notice what people already care about, then bring a useful proof, tool, teardown, or question that makes the conversation better. I would run it small enough to learn quickly, then only scale the parts that real users repeat, save, reply to, or buy from. For this tactic, I would watch 50% of signups came from private Slack chan before putting more time or budget behind it.

## Action plan

1. Define one narrow startup segment where free-text signup attribution for dark funnel discovery can create a measurable lift.
2. Turn the tactic into one offer, page, campaign, or workflow for the Communities and Referrals channel.
3. Use the evidence from postiv.ai to set the first version of the message, format, and audience.
4. Launch a small test for 7 to 14 days with one success metric: 50% of signups came from private Slack chan.
5. Review the result, keep the winning message, remove weak variants, and turn the learning into a repeatable growth playbook.

## Source-backed example

Documented by http://Postiv.ai (February 2026) across hundreds of SaaS founders — those who replaced dropdown attribution with a free-text field consistently discovered that 30-50% of signups came from private Slack channels, forwarded newsletters, DM recommendations, and other dark funnel sources invisible to analytics.

## Adjacent tactics in the same lane

- [AI chatbot onboarding for activation](/growth-ideas/ai-chatbot-onboarding-for-activation/) - same source, 2 shared channels, 2 shared stages
- [Dark funnel community seeding](/growth-ideas/dark-funnel-community-seeding/) - same source, 1 shared channel, 2 shared stages
- [PLG with sales-assist triggers](/growth-ideas/plg-with-sales-assist-triggers/) - same source, 1 shared channel, 2 shared stages
- [Staggered multi-platform launch sequence](/growth-ideas/staggered-multi-platform-launch-sequence/) - same source, 1 shared channel, 2 shared stages

## Read GrowthDex essays

Browse the plain-English essay index at [GrowthDex Blog](/blog/).

## Advisory

If you want help turning this into a working growth system, Ian Goh offers advisory at https://iangoh.com/advisory.