1.) from Facebook's page to advertisers:

Facebook Ads

Pair your targeted ad with related actions from a user's friends.

Advanced Targeting:
Target by age, gender, location, interests, and more.
Content Integration:
Get noticed, not skipped.
Flexible Pricing:
Buy clicks (CPC) or impressions (CPM).
Trusted Referrals:
Attach friend-to-friend interactions about your business to your ads.

But my favourite part:

Viral Distribution:
Users' interactions with your Page spread naturally to their friends.

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