You can buy attention (advertising). You can beg for attention from the media (PR). You can bug people one at a time to get attention (sales). Or you can earn attention by creating something interesting and valuable and then publishing it online for free.
David Meerman Scott,
online marketing strategist and author of several books on marketing,
including The New Rules of Marketing and PR
Quote taken from https://www.davidmeermanscott.com/blog/2009/12/social-media-marketing-explained-in-61-words.