A thumbnail understanding of Google Ads and Facebook ads and promoted posts:
Google Ads: comparable to the yellow pages or classified ads
Google Ads is search-based. Users are looking for your service or product and Google Ads puts you in their search results. The more you are willing to pay per click, the higher you’ll appear in the results. Google Ads offers keyword targeting, and allows you to target by location. It also offers negative keywords for excluding clicks that you do not want.
Facebook: comparable to television and radio ads
Facebook ads and promoted posts are like mass media—newspapers, television and radio. Use Facebook for upcoming events, to make your brand known, or to promote a candidate or ballot measure. Facebook allows you to target users based on location and demographics, but you are competing for attention in users’ newsfeed.