It's a pretty weak article, if they wanted to drive traffic to their site why were they focusing on getting likes rather than CTR ?
Doing internal FB advertising only really makes sense if you have a strong FB presence (i.e. Facebook game or if you push lots of sharable content via your FB page).
Exactly. They went about it backwards. They should have focused on driving traffic (website clicks). A successful traffic-driving campaign has a byproduct of likes. Even better, those likes tend to be people who used and actually liked your product, rather than those who just clicked like.
NOTE: If you have less than 1000 likes, you should pay for likes until you get up to that number, as it unlocks some advertiser features.
Doing internal FB advertising only really makes sense if you have a strong FB presence (i.e. Facebook game or if you push lots of sharable content via your FB page).