The only time when Free can really work for you is if you set your sights on having a specific outcome: acquisition. If you’re building technology, or a team, that is valuable to somebody else than you can afford to provide a free service and raise finance to fund that service until you’re in a position to be acquired.

On September 1st, 2009 we announced that MailChimp was going freemium. On that day, we had 85,000 users. Now, slightly more than a year later, we have more than 450,000 users. We grew our user base five times in one year.

Sure, some customers will complain, and others might take their business elsewhere. But there’s a good chance you don’t want those kinds of customers, anyway.