Former Sun Microsystems CEO Scott McNealy’s re-entry to the computer industry is drawing some serious interest from vendors as a handful of well-heeled industry veterans have just poured $15.4 million into Wayin, the real-time social marketing company he now heads.

In addition to McNealy himself, investors in this latest round include David Duffield, founder of PeopleSoft, Inc. and co-founder and chairman of Workday, Inc., and existing backers U.S. Venture Partners and SAP AG founder Hasso Plattner.

Wayin enables marketers to create interactive campaigns using content mined from the social Web and submitted by visitors. Brands can monitor conversations about their products and campaigns in real time and feed social data into the campaigns themselves. Several of Wayin’s engagements with prominent customers like Dunkin’ Brands Inc.’s Dunkin’ Donuts and The Coca-Cola Company have incorporated interactive voting, with results displayed immediately inside the campaigns.

Wayin also provides a sophisticated set of tools for analyzing sentiment, identifying trending topics and profiling influential people in social media. The company said it will use the new cash infusion to expand its sales force, engineering department, creative studio and international presence.