Facebook is in the news almost daily and the social network continues to grow, with more than 500 million members at last count. And Top 500 retailers want to be right there with them. 432 of the companies listed in Internet Retailer’s 2011 Top 500 Guide —86%—have a presence on Facebook. That’s 16% more than the 371 that had pages on Facebook last year and a 52% increase from 284 in the 2009 edition.

While Facebook nears full penetration among Top 500 web retailers,  it’s Twitter that is seeing the greatest growth, followed by YouTube. MySpace use, by comparison, was static for two years and now is tailing off.

Twitter, the network that enables users to “follow” the daily doings of other participants via 140-character message bursts, continues to grow in web retailers’ social media strategy. Of the current Top 500 online retailers, 347, or 69%, have a presence on Twitter and feeds are up by 37% (254 companies) from the 2010 edition and 221% (108) from the 2009 guide.

The growing adoption of social media marketing reflects a new understanding by web retailers of today’s shoppers, says Jeff Zabin, research director at Gleanster, a Chicago-based digital marketing research firm. “Retailers are going to allocate more of their resources to interacting with consumers through social resources, because that’s where consumers want to spend their time,” he says. “Brands are waking up to the fact they need to listen to the customer, the online voice. Then they need to be sure they are creating marketing messages resonating with consumers.”

Retailers can tune into Twitter and other sources of consumer-generated content and identify unmet wants and needs that can drive new product development, Zabin says.

YouTube is the most visually enticing mode of social interaction with consumers, and 316 Top 500 retailers (63%) posted commercials, product demos or other types of videos on the video site owned by Google Inc., compared with 269 (54%) last year and 207 (41%) in the 2009 edition. Use of YouTube can only grow, Zabin predicts. “One objective in social marketing is to generate buzz and pass-alongs,” Zabin  says. “If people are entertained or informed they are more likely to pass along a video to a friend.”

Use of MySpace by online retailers fell 6.2% in this year’s Top 500 Guide, to 137 (27% of the Top 500) from 146 (29%) in the previous edition. The network was tapped by 143 (nearly 29%) of the Top 500 in the 2009 edition.

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