• by David Goetzl  @dgoetzl, April 21, 2010

CAPTIVA ISLAND, Fla. -- The Indianapolis business community includes the operator of a Caesars Palace mall, the marketer of Cialis, pitchman Peyton Manning and the growing "Silicon Prairie."

It's unclear whether the successor term to Silicon Valley and New York's copycat Silicon Alley is just a casual one, but Central Indiana has a moniker for its thriving digital marketing community. MediaPost has covered the expansion, which continues to help the economy. (Omaha also claims the nickname.)

"It's a term I use to describe the energy going on there," said Joel Book, director, eMarketing Education at ExactTarget. "There's a tremendous amount of energy that's rooted in these companies."

Email service provider ExactTarget played a stimulus package role last year as it more than doubled its employees to 500, and saw revenues leap up 30% to cross the $100 million barrier. Aprimo, an integrated marketing software company, had 15% revenue growth amid the recession to $68 million.

Both companies had executives at MediaPost's Email Insider Summit that wrapped on Wednesday. Other Hoosier tech operations include ChaCha in the mobile space, Compendium Blogware that helps businesses with blogging and Right On Interactive in marketing automation.

Growing companies spawn spinoffs a la Northern California and Boston. In 2007, ExactTarget co-founder Chris Baggott left to launch Compendium. A year before, Troy Burk left ExactTarget to found Right On, which last year pledged to add 100 jobs.

TechPoint, an Indiana technology trade association, estimated the industry contributed more than $4 billion to the Indiana economy in 2009. ExactTarget hosts an annual conference that brought 1,300 visitors to town in 2009 and had an estimated $1 million impact on the Indy economy.

Some of the tech growth has been helped by Gov. Mitch Daniels' support. The state provides tax credits, patent income exemptions and R&D sales tax exemptions.

"He's absolutely lent his voice to championing the cause and calling attention to it," ExactTarget's Book said.

The growth of the digital economy has also persuaded a run of executives to relocate to Indianapolis, such as ExactTarget's CMO Tim Kopp, who joined in 2008. Book was in Kansas City.

Book said the rise in tech jobs has helped stem a possible brain drain, keeping college grads from Indiana, Purdue and Ball State in the state.

"Definitely Indianapolis has become a really great place to work and live if you're a young professional, and you have an interest in (digital marketing)," Book said.