• by Gavin O'Malley  @mp_gavin, October 1, 2012

Ripe for a political talking point, new data shows that employment in the ad-supported Web ecosystem doubled over the past four years to 5.1 million.

Better yet, the same digital ecosystem contributed $530 billion to the U.S. economy last year -- close to double the 2007 figures, according to the Harvard University Business School. The research was commissioned by the Interactive Advertising Bureau.

That dollar amount accounted for 3.7% of the U.S. gross domestic product -- an uptick from 2.1% four years ago, the HBS reports.

“One of the most striking findings of this report is that growth was fast in the consumer-facing layer, but that it was even faster in the less glamorous infrastructure layer that supports the high-profile brand name sites and services” said John Deighton, Harold M. Brierley professor of business administration at Harvard Business School, who authored the report with Leora Kornfeld, research associate at Harvard Business School.

“Jobs grew fastest in digital advertising agencies, ad networks, ad exchanges, customer analytics firms and listening platforms,” Deighton added. “The engine of growth was not just consumer-facing companies like Facebook, Twitter and YouTube, but also firms that used the data spun off by them.”

The ad-supported digital industry directly employs 2 million Americans, and indirectly employs a further 3.1 million in other sectors.

The report shows New York and California as home to the headquarters of the largest number of U.S. Web firms. More interestingly, perhaps, is the revelation that Washington, Massachusetts and Illinois rank as the next three most digital-friendly states.

In total, nine states are the sites of headquarters that account for 72% of attributed employment, although the jobs themselves were dispersed across other states in the union, the report shows.

That said, every Congressional district in the U.S. was home to at least a handful of companies within the Web ecosystem, and many had thousands of such companies, per the report.

Overall, job creation was highly dispersed, with less growth in aggregate and in percentage terms in the so-called “megaplexes” of Google, Microsoft and Yahoo than in the tiny entrepreneurial ventures across every state and county.

Sole proprietors and small firms were cited as the big winners, this year. They contributed 375,000 full-time equivalent jobs to the 2 million in the Internet ecosystem.

Many were selling on Amazon, eBay and Etsy, while other others were self-employed Web designers, writers and programmers. App development alone accounted for 35,000 full-time equivalent jobs, and the number of moonlighters was an order of magnitude larger.