User blog comment:Atarumaster88/Wikia's New Feature/@comment-1978336-20140401035807/@comment-20644-20140401050534

Making it bigger ensures that people see it, and that it receives higher levels of engagements. There was actually extensive user testing done around this. When a smaller version was added to pages during tests, we found that 1% of visitors clicked "Like." But with a larger button, that became 36%. That is a huge jump, so we went with what works.