The document summarizes hot trends in social networks, mobile marketing, and online video according to a senior analyst from eMarketer Inc. It finds that while social network growth is slowing, advertisers are experimenting with new ad formats on networks like Facebook. Mobile marketing is growing faster than mobile subscribers, with messaging being a top format. Online video viewing is widespread, though video ads have yet to challenge other formats for spending. Factors like broadband growth and improved targeting could boost video advertising.