The theory goes that Youtube, and the «Youtubers» who produce hours of footage of themselves playing and commenting on games are now as vital a marketing tool for video games as the more traditional print - and television - ads. (clockworkmanual.com)
For example, if you've written a local history book about the region you live in and are familiar with, word of mouth may be the most vital marketing tool available to you. (lulu.com)
Facebook and Twitter have become vital marketing tools for building brand loyalty among current customers and attracting new followers. (petbusiness.com)