Among the world's most valuable brands, Starbucks, Dell, eBay, Google, and Microsoft best leverage social media to interact with customers online, according to a study by Altimeter Group and Wetpaint (via Techcrunch).

The ENGAGEMENTdb study (pdf), led by analyst Charlene Li, a Partner at Altimeter, determined the engagement score of the brands by looking at their use of 11 social-media channels and their level of engagement within each channel.

Engagement by Industry

Perhaps not surprisingly, the top brands' industries among most engaged on the Web are media, technology, and retail. The least engaged are the financial, apparel, and manufacturing industries.

Media, the leading industry in engagement among top brands, is led by Google, followed by Thomson Reuters:

An Engagement Payoff?

The study sees a correlation between social-media engagement and revenue: The revenues of those most engaged increased, on average, 18% over the past 12 months, whereas the revenues of those least engaged fell, on average, 6%.

Despite the apparent correlation, it's not clear whether there's a cause-affect relationship between social-media engagement and revenue growth.

(Visit the ENGAGEMENTdb study online and try out its various interactive features.)