Zoe Strauss is a genius - not at photography, at which she's merely talented, but at marketing.

She developed one brilliant concept, an annual outdoor exhibition of her work under the I-95 elevated expressway in South Philadelphia, then parlayed that into inclusion in the 2006 Whitney Biennial, and now into a mid-career retrospective at the Philadelphia Museum of Art.

This level of professional success would take most artists far longer, if they managed to achieve it at all. Few do. Yet Strauss, who will turn 42 on April 1, has conquered two career peaks in little more than 10 years as a committed photographer.

Like many Internet Age artists, she has worked assiduously at promoting her work through blogging and social media.

Yet that alone doesn't explain why she has become a local phenomenon. Her effervescent personality and infectious enthusiasm have helped. Not only did she charm the media at the press preview of her show, a day later about 2,000 fans and supporters crowded into the museum for a dance party - with ?uestlove! - to celebrate the public opening.

Strauss' photographs seem to speak forcefully to members of her own generation, but even that isn't the whole story. The key, I think, is her passion to involve the public in her image-making and storytelling, both as subjects and as audience.

She began to do this with the "Under I-95" shows, where her color prints on photocopy paper, priced at $5 apiece, were displayed on the roadway's support columns for a single day.

For the museum, Strauss has extended this Gallery Alfresco strategy to 54 billboards around the city. Most of these large-scale images will be up at least through March 26.

Putting art on billboards isn't any more innovative than the types of photos Strauss makes, but her populist outreach feels like a natural extension of her working philosophy, to "present an epic narrative about the beauty and struggle of everyday life."

When one considers the 146 color prints hanging, a bit too snugly, in the museum's Honickman and Berman galleries and the 54 billboards, struggle seems to predominate.

She clearly identifies, and empathizes, with people living on the margin of polite society.

She also displays a gift for friendship with strangers that allows her what is often a startling degree of intimacy in photographing them.

A city native, Strauss has lived in South Philadelphia for many years. Many of her photos were made here and in Camden, although the show includes some from the Louisiana Gulf Coast and Las Vegas, where her family lived briefly when she was a child, and a few other locations.

As a street photographer recording evidence of daily existence as she encounters it, she makes the kinds of images that we have seen from many other photographers, such as Walker Evans and William Eggleston - casual portraits (which with Strauss aren't always so casual), messages conveyed through signs and graffiti (Mom Were OK), glimpses of architectural patterning.

The show includes a few landscapes, strikingly abstracted, but these only serve to emphasize that Strauss is mainly interested in people, how they present themselves and express their feelings and personalities.

She sees her subjects, some of whom are friends and neighbors, as individuals, not as social types.

One portrait, on a billboard at Passyunk Avenue and Reed Street, conveys this quality with noticeable vigor. It's a typically frontal, close-up portrait of one of Strauss' neighbors, Antoinette Conti (who will be replaced during March and April by another friend, Fernando Trevino).

As a group, Strauss' portraits are arguably her strongest pictures, in part because they're her most individualistic work. They include men and women of all ages and races whose common denominator appears to be that they're apparently living on limited means, and not in Society Hill, Rittenhouse Square, or Chestnut Hill.

The portraits aren't confrontational, because Strauss isn't a muckraker or a thrill-seeking voyeur.

A few images made me think of more diaristic photographers such as Nan Goldin (Ken and Don) and Donna Ferrato (Monique Shows Black Eye), but more often Strauss conveys the grimmer side of existence through graffiti (Beth is a rat) and tattoos (Thug Life, incongruously paired with a crucifix on a hairy chest).

One senses that most, if not all, of Strauss' pictures incorporate stories. Some of these can be inferred, and usually the absence of interpretive commentary doesn't impede one's ability to grasp the essential messages.

It's more of a problem with the billboards. Attractive as this strategy is - it extends the museum's reach physically into the community - the billboards are, paradoxically, less communicative than traditional prints.

They can be hard to see; they're all commercial spaces that usually carry bold advertisements designed to project for a distance.

Not all Strauss' pictures do that; the aforementioned one at Passyunk and Reed, which commands a supermarket parking lot, is one that does.

Furthermore, some billboards need backstory to be fully appreciated. Several I saw on press day prove the point.

One, at 34th Street and Grays Ferry Avenue, depicts a woman holding up a shirt. It helps to know that the shirt belonged to her late husband, who was exposed to high levels of radiation at a nuclear weapons facility.

Juxtaposed with that photo is one of the Three Mile Island nuclear generating plant near Harrisburg. Together, the photos express the photographer's acute social consciousness, but only if you're aware of their contexts.

Just west of 30th Street Station, Strauss has juxtaposed a photo of a handmade sign that says "Don't Forget Us," a relic of Hurricane Katrina, with one of houses on Osage Avenue, relics of a notorious man-made disaster here. Again, context needs to be understood.

Given that billboards, especially those high off the road, can be hard to read, or even notice, when people are zipping past in cars, I question how effective this part of Strauss' project will prove to be. Drivers might take them for ads in process, or simply be puzzled.

One must acknowledge, however, that the Strauss exhibition generates considerable emotional resonance. It's this quality that elevates her work above the routine; somehow she manages to communicate the feeling that she really cares.

Art: A Common Touch

"Zoe Strauss: Ten Years" continues at the Philadelphia Museum of Art, 26th Street and the Parkway, and on 54 billboards across the city, through April 22 (billboards come down sooner). Hours are 10 a.m. to 5 p.m. Tuesdays through Sundays, to 8:45 p.m. Fridays. Admission is $16 general, $14 for visitors 65 and older, and $12 for students with ID and visitors 13 to 18. Information: 215-763-8100 or www.philamuseum.org.


Contact contributing art critic Edward J. Sozanski at 215-854-5595 or esozanski@phillynews.com. Read his recent work at http://go.philly.com/edwardsozanski.