While page administrators could always suggest their own content to friends, Facebook never asked users to promote other pages before. So we wonder what determines whether or not this box is displayed to users. Is it based on how often a user engages with a page? Is it based on how much money that page is spending on advertising? Perhaps it’s completely random.
However I’d seriously doubt that Facebook would implement a new feature without measuring its performance. Whether or not this feature will become more widespread is unknown, but it’s definitely an interesting feature that will impact the number of organic friends which pages are able to attract.
Thanks to Kevin Evanetski of SocialYeah for the tip!