Remember that in a lot of cases you're not comparing against the cost of online advertising, you're comparing against the cost of an external salesforce. Many

Remember that in a lot of cases you're not comparing against the cost of online advertising, you're comparing against the cost of an external salesforce. Many businesses are perfectly happy to spend 10k to acquire a customer who'll pay them 50k over the next three years. Assuming you're not running hugely expensive hackathons a low conversion rate can still give a decent ROI. Even if you CAC is relatively low you can still make hackathon commercially viable. A lot of smaller vendors will partner together to split the cost of hackathons between them or will become external sponsors to third-party hackathons in order to reduce the costs involved.