Have a competition, worldwide, where photographers and general public can vote on best filter use. It can be 2 different tiers: standalone categories with Filter Forge 4.0, 5.0 and 6.0 where the winner of 4.0 and 5.0 get a free upgrade to 6.0 and 6.0 gets a free upgrade to the next release. The 2nd tier would be an all inclusive tier for best with in an app inclusion, where the winner gets a free upgrade to next release. Post it on Facebook and Twitter.