[Quizz]

I'm using Yesware freemium and think it's cool for personal use but have not experienced the 'must have' epiphany yet to upgrade.

[PeterisP]

This is a key issue for freemium companies - your free product needs to be good, but there needs to be a clear, sufficiently large audience for whom the free product would not be sufficient and they'd need to buy the upgrade.