I can only guess it's because he was faaar too generous with the credits. One article per day? I send maybe one-two per week. Maybe a better solution would be to give each user 5 credits total, and then they would have to pay to keep sending articles(I would do it as an unlock thing, rather than selling them more credits though).
yeah... definitely. Cut back on the free offering, and make it "pay to use" for anyone who ends up using it anything resembling daily.
Also probably worth making it a subscription ($1/month?) instead of credit-based - subscriptions can give dependable revenue, and users wouldn't feel nickle'd and dime'd.
Anyhow, the simple lesson here is that freemium isn't a magic bullet - probably takes some time to figure out the right place to put the paywall to get growth / usage via free users, and revenue from not giving everything away for free.
