Hallie Mummert

The U.S. audience watching online video continues to build, hitting a high of 86.5 million Internet users in December 2009, according to marketing research firm comScore. While a good deal of these folks are laughing along with giggly babies and checking out videos from their favorite entertainers, plenty of consumers and businesspeople also are tuning in to how-to demos, product announcements, event keynotes and other types of marketing content.