Started by 1 and 2. People like 3,4 have “signed up” for it and 5 is the latest addition to the list. What are we talking about?

P.S: There is a question in-between the two pic-heavy posts.. In case you missed it

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Answer:
Billionaires like Bill G and Warren Buffet have signed up to give out half their wealth in a campaign called “The Giving Pledge”. Thats very nice of them. Don’t you think?