Quote from the book "487 хаков для интернет-маркетологов: Как получить еще больше трафика и продаж"

Suitable for smartphones, Android tablets, e-readers (except Kindle) and many programs

Can be opened on almost any device

Can be opened on any computer

Can be opened on any computer

Opens in Adobe Reader

Optimized and suitable for smartphones

Suitable for Kindle e-readers and Android apps

Development of FB2 format