Dropbox's referral offer is the first entry in our list of top 50 startup offers that won customers. This playbook covers only the offer: its terms, who it was for, why it worked and how you could run a similar one. For the wider company story, read our Dropbox case study.
What was Dropbox's referral offer?
The idea was simple. If you told a friend about Dropbox and they signed up, you both got free extra storage. On Sequoia's "Crucible Moments" podcast about Dropbox, the programme was described as "this two-sided incentive where you would get some free space; I would get some free space."[13]
At first, Dropbox gave 250 MB per invite.[3] It then doubled the reward for students, and later decided to give the doubled reward to everyone.[3] By April 2012, for every friend who installed Dropbox, both people got 500 MB.[6][7] Dropbox also applied the new rate to referrals users had already made.[6]
| Period | Who it applied to | Reward per completed referral | Cap |
|---|---|---|---|
| Early years (before Oct 2010) | All users | 250 MB per invite[3] | Not stated in the sources cited here |
| 6 Oct 2010 | Free users with .edu email addresses | Double credit: 500 MB per invite[4] | Not stated |
| "Schoolbox" campaign | All school-goers | Double credit: 500 MB per invite for free users[5] | Not stated |
| April 2012 | Everyone | Free accounts: 500 MB each for inviter and friend. Pro accounts: 1 GB per referral[3][6][7] | Free: 32 invites, 16 GB. Pro: 32 GB[3] |
| 15 Oct 2012 ("Space Race", one-off) | Students | 3 GB for two years on signup, with the chance to win up to 25 GB for two years[15] | 25 GB[15] |
| Current terms (checked Oct 2026) | Basic, Plus, Family, Professional | Basic: 500 MB. Plus: 1 GB. Friend: 500 MB[8][10] | Basic: 16 GB. Paid personal plans: 32 GB[8][9] |
The reward is not always equal today. A Plus user earns 1 GB per referral, but the friend who joins gets 500 MB.[8][10] For context, a free Basic account starts with 2 GB.[11] That means a full set of referrals can give a free user much more space than they start with.
The reward depended on the friend actually using the product. In the 2012 terms, both people got the space only when the invited friend installed Dropbox.[7]
Who was it for?
The offer worked through Dropbox's existing users, who were asked to bring in friends. Most Dropbox users were on the free plan: as of 31 December 2017, it had over 500 million registered users but only 11 million paying users.[14]
Students got special attention. They received double credit from October 2010, and later the Space Race campaign.[4][5][15]
Some users were deliberately left out. People on Dropbox team (business) accounts can't send referrals.[8]
When did it run, and why then?
Houston's slides list a cost per acquisition of $233–$388.[1] The slides we reviewed don't tie that figure to a specific date or to the launch of the referral offer.
The sources we reviewed give no exact launch date for the offer. The slides show Dropbox at 100,000 registered users in September 2008.[1]
The slides say the offer was "inspired by PayPal $5 signup bonus".[1] On Sequoia's podcast, the two-sided design was traced to a memory slip: "the two-sidedness was actually me misremembering."[13]
Why did it work?
- Both sides gained (reciprocity). The person sending the invite was giving the friend something, not just asking a favour. Houston's slides say the referral programme with a two-sided incentive "permanently increased signups by 60%".[1]
- The reward was the product. Extra storage only has value if you keep using Dropbox. So the bonus made people use the product more, rather than handing out cash. It also made the free plan more useful.
- The reward was tied to installs. In the 2012 terms, the space was given "for every friend you invite that installs Dropbox."[7] That linked the reward to the friend actually installing the product rather than just entering an email.
- Storage was the currency, not ad spend. Dropbox paid for the offer through storage and infrastructure. Its IPO filing lists expenses for the storage, delivery and distribution of its platform for both paying and Basic users.[14] Our sources don't report a cost per referral, so a direct comparison with the $233–$388 cost per acquisition in Houston's slides isn't possible.[1] But the filing says Dropbox acquires users "efficiently and at relatively low costs through word-of-mouth referrals."[14]
What were the results?
| Date | Result | Source |
|---|---|---|
| First 10 days (recalled later) | Users rose from about 100,000 to 200,000 "in the first 10 days", as recalled on Sequoia's podcast | [13] |
| Reported in Houston's slides | The two-sided referral programme had permanently increased signups by 60% | [1] |
| Reported in Houston's slides | 35% of daily signups came from the referral programme | [1] |
| 30 days to April 2010 | Users sent 2.8 million direct referral invites | [2] |
| 31 Dec 2017 | Over 500 million registered users, of whom 11 million were paying | [14] |
On Sequoia's podcast, the effect was remembered this way: "we basically doubled our growth rate overnight."[13] That is a later recollection. The 60% figure from Houston's slides is the more reliable number.
Some retellings of this story get the numbers wrong. The slides give the referral programme 35% of daily signups, not all of them.[1] And "2.8 million" was the number of invites sent in 30 days, not the number of new users.[2]
The 2018 IPO filing says, "Our 500 million registered users are our best salespeople."[14] The filing credits word-of-mouth referrals, but it gives no separate numbers for the storage-bonus programme.
What did it cost, and what went wrong?
We know it paid in storage and the systems behind it, as part of the cost of serving free and paid users.[14] Treat any exact cost figure you see online with suspicion.
A free product that rewards sign-ups will attract abuse. Dropbox's Acceptable Use Policy bans using referrals or promotions "to get more storage space than deserved."[12] Rewards are also capped, and team accounts can't send referrals.[8]
None of the sources we reviewed report action by regulators or losses linked to the programme. The offer is still running, with caps of 16 GB on Basic and 32 GB on paid personal plans.[8][9]
How to run a similar offer on a startup budget
- Make your product the reward, and give it to both people. Choose something that costs you little to provide but means a lot to the user: extra credits, a free month, more seats or more usage. Avoid cash, which attracts fraud and does nothing to make people use your product.
- Reward only real activation. Decide what counts as a real user, such as a first order, a completed profile or a first upload. Like Dropbox, which tied the reward to the friend installing the app, give nothing until the friend has done it. Set a cap per user, block existing accounts and repeat devices, and put an anti-abuse clause in your terms.
- Test with one group before opening it to everyone. Dropbox tried a bigger reward on students first and then gave it to all users. You could start with one city, one college or your most active customers, and grow from there.
- Tell people about the offer. A referral offer only works if people know it exists. Haatopia's Referral Launch Kit gives you 20 creatives (120 credits), 40 short-form posts (80 credits) and 25 disclosed expert answers (50 credits), all made and posted by our executives. That is 250 credits in total, roughly ₹4,250–5,000 depending on the pack. See campaign kits and pricing, or use the Campaign Finder to compare it with other options.
- Watch one number: the share of new active users who came through referrals. Dropbox tracked this as a share of daily signups. Also compare your cost per active referred user with what you pay for a customer through ads. Stop or redesign the offer if referral costs get close to your ad costs, or if many rewards are being rejected as abuse.
When not to use this offer
- When each new user costs you a lot to serve. If your reward is a physical product or an expensive service, a two-sided offer can lose money quickly.
- Before people already like and talk about your product. Dropbox's IPO filing says it acquires users "efficiently and at relatively low costs through word-of-mouth referrals."[14] A referral reward makes existing word of mouth spread faster. It cannot make people recommend a product they don't like.
- When the buyer isn't the user. Dropbox keeps team accounts out of its referral programme.[8] In company sales where a purchasing team decides, a referral bonus to individual users rarely changes the decision.
- When fake sign-ups are cheap to create and hard to catch. Without checks for activation and duplicate devices, you end up paying for fake accounts instead of real customers.
