You collected the user's email addresses during signup right? You should send each one of them a reminder email, and maybe list the outstanding bugs they haven'

You collected the user's email addresses during signup right? You should send each one of them a reminder email, and maybe list the outstanding bugs they haven't closed yet. You were able to convince 150 people to sign up for your app, you should remind them about it. I remember seeing a chart somewhere recently which showed that on average a person needs to be reminded of something about 4 times before it sticks in their memory.