Companies know that Facebook is the most important social network for reaching consumers. That’s because 73% of Americans use Facebook every day, compared with 27% who use Twitter that much and just 17% who look at LinkedIn every day, according to a recent survey by Springboard America, a market research provider.

For the same reason, Facebook is a crucial platform for the leaders of those companies: When social-media usage is so overwhelmingly skewed toward Facebook, CEOs can’t afford to limit their professional online presence...