Starting this week, we are bringing a new feature to the table for all our Business and Enterprise users. Now, you'll have the option to embed content in your flipbook using any embed code that has the iFrame tag.
In order to take advantage of this feature, click on the Interactions tab while in the Design Editor, and you will have the Embed option on the right.
After you select Embed, click on the Add code button at the top and add your iFrame into the text box.
Please let us know what you think about this feature via live chat.