In April, the cable network ESPN launched its first city-specific website, ESPNChicago.com, choosing Chicago over other sports-obsessed cities. The decision follows those of several other national media outlets looking to focus more on customized news that have found Chicago to be the “It” local spot to expand their business models.

In November 2007, BusinessWeek launched a monthly print edition, BW Chicago, and last August, The Huffington Post brought its national brand here. So did the satirical newspaper The Onion, which debuted its localized online entertainment site, Decider, just weeks later.

Jim Pastor, of ESPN’s digital media ventures, says the success of ESPN’s radio affiliate in Chicago (WMVP-AM 1000) paved the way for the network to try out the Web. Pastor says ESPNChicago.com received more than five million page views in its first month: “Chicago turned out to be a perfect launch city for us.”

Arianna Huffington, founder of The Huffington Post, says her Chicago experiment has worked, too, and in June her company ventured into New York.

So, what makes Chicago such an attractive media testing ground?

First off, Chicago is a great news town, says Michael Smith, executive director of the Media Management Center at Northwestern’s Medill School of Journalism: “People just want to know more here. It’s a Midwestern theme.”

With more than nine million people, the Chicago area also has the size—don’t count on ever seeing an ESPNSiouxCity.com or a Huffington Post Eau Claire—and it is well placed in the cultural heartland of the country, not on the coasts. “New York represents the media, and L.A. represents entertainment,” says Rex Sorgatz, a New York–based media consultant and the former executive producer of MSNBC.com. “Chicago still has the market size and represents what people think outside the obsessive, chattering classes.”

Of course, success isn’t guaranteed. Just eight editions of BW Chicago came out before the magazine folded. The former editor, Michael Arndt, says the magazine was well received editorially, but advertising revenues fell short.

Chicagoans, meanwhile, can expect to see the trend continue. “You’re going to see more and more local initiatives coming out of midsized media companies in Chicago and elsewhere,” says Sorgatz.