A recession may be upon us, and some categories of media are hurting, but one that continues to hold up is out of home.

Outdoor advertising revenue in 2007 reached $7.28 billion, up 7 percent versus 2006, according to data released this week by the Outdoor Advertising Association of America. That’s slightly down from 8 percent growth in 2006, but still about twice the growth pace for all media for 2007.

This continues a trend of the recent several years, the result of technological improvements, such as better reproduction of billboard images, and better measurement of the medium, which has brought in advertisers who might night have used out of home in the past.

But it also reflects a more mobile population, says Stephen Freitas, chief marketing officer for the OAAA. “Consumers are more mobile and spending more time out of the home, while other media is fragmenting and losing audience share. Out-of-home advertising is a good way to get back that share.”

The fastest-growing category in outdoor advertising in 2007 was far and away communications, much of that for cell phone services. The category jumped 35.7 percent year-to-year, to more than $655 million in spending.

“There’s been a lot of competition with some of the big brands, such as AT&T and Verizon,” Freitas says. “They’re spending more in out-of-home and across the board.”

He also says cable and satellite TV companies such as Comcast and DirecTV also factor into this category, with increased spending as they try to attract subscribers.

“There’s so much innovation going on in that sector, and that drives lot of advertising,” Freitas says.

Also, while woes in the housing market have caused turmoil in that industry, it’s actually led to an increase in outdoor ad spending. The insurance and real estate category was No. 2 overall and grew 9.2 percent year-to-year, to about $721 million in spending.

“At a time when the real estate market has shown declines, the successful agents want their brand out in the market place,” Freitas says. “They want people to feel they have they have their finger on the pulse of the market.”

Just three of the top 10 outdoor ad categories showed negative growth in 2007 versus 2006. Retail was the biggest loser, dropping 4.7 percent to about $590 million in spending.