What are the motives behind facebook 'share' and 'like' donation?

[l540l]

Every day, on my newsfeed, there are some 'shared' images / news concerning 'poor / unfortunate / cancer / and other sorts of people' that requires us to either click 'share' or 'like' in order to have a certain amount of money being 'donated' to them. How true are these? Were they any true cases that facebook actually donates money to every clicks of shares and likes we give, or they are only spam or probably spyware that will locate our account if we click on them?
Getting attention and have their profile / message being spammed all over other unknown user's account could be a reason to it, but i don't really think it's that simple. Or it really is?

[oli]

They do it so their page or group starts trending around.

[Fadi]

To get attention.