As many others in here I'm continuously working on start-up ideas when my day-job is over. One of these is nearing it's beta phase. Ideally I'd do a closed beta-test for invite users only. They would have to expect all their data to be lost after the closed beta period. What is the best strategy to attract such users? It's no exactly "Show HN"-material as it's far from a finished product. But I'd like to get early feedback from users that does not expect to much..