Giving What We Can — Website: http://www.givingwhatwecan.org/

Note: The source text explicitly lists 'official website http://www.givingwhatwecan.org/' in the Wikidata entry for Giving What We Can (Q5565874). The claimed URL matches exactly with the source, with only minor formatting differences (http vs www prefix variations are not contradictions per the guidelines). This directly confirms the claim.