Ann Montchyk doesn't have to tell you that she's a Phillies fan, a Christian, and a political conservative. Her 2005 Toyota Camry - specifically the many stickers on its bumper - does that for her. Her car is a mobile messaging system, her way of expressing her views while encouraging others to share them.

"I want people to think about these things," said Montchyk, 88, of Erdenheim. "If they're stuck at a traffic light, staring, they're reminded."

It's easy to get lost in the crowd of the billions of humans crowding the planet. So to help carve out our niche, we wear pithy T-shirts or stick political signs in our yards or click Facebook "likes."

Bumper stickers, nearly as old as bumpers, can be funny, political, or thoughtful. They can show family pride, in the form of a stick family in the window, an honor student indicator, or a college decal.

They can seek to motivate behavior, encouraging the other drivers to "practice random acts of kindness" or watch out for the baby in the car. They can be threatening, warning others not to drive too close, or not to boast about that honor student too loudly.

While the messages can divide us, they can also bring us together. Stickers and their like - window clings, decals, personalized license plates - all provide "an opportunity for conversation," said Temple University professor Frank Farley.

"Self-expression is a powerful human motive," said Farley, also a former president of the American Psychological Association. "Bumper stickers are just another vehicle of expression."

To a certain degree, it's fair to draw some conclusions about people based on what's on their car. People choose their stickers for the statements they're trying to make, said David Stillwell, a researcher at the Psychometrics Centre at the University of Cambridge. It's similar to a study he coauthored that concluded Facebook "likes" can, among other things, predict a user's gender, ethnicity, intelligence, sexuality, and personality.

"Everyone wants others to know what makes them unique, and what are important issues for them," Stillwell said. "Likes are such a good indication of personality, because we choose a few tens of things to like out of 100 billion potential Likes.

"The same applies to bumper stickers: You can only fit a limited number of stickers on your car, so you have to choose the most important and expressive stickers."

Bumper stickers also reveal driver aggressiveness, no matter how much peace and love the stickers preach. A 2008 Colorado State University study concluded that people who had a large number of "personalized items" on their vehicles were 16 percent more likely to commit an act of road rage.

When Montchyk sees a sticker she doesn't agree with on the road, "I pray for them." In a similar vein, lifelong Philadelphian and sports fan Robert Lawley keeps his cool when he sees opposing viewpoints, such as the two Dallas Cowboys helmet decals affixed to a car parked not far from his in a South Philadelphia parking lot.

"It's free speech," said Lawley, 59, of South Philadelphia, whose stickers include "Defend America. Defeat Bush." "I may not agree with it. It may make me mad. But it's OK."

Amanda Abramson said stickers and decals represent what people are proud of or enjoy. Her SUV has two window decals - one for Ocean City, her favorite beach, and one for Friends Select, her daughter's school. An animal lover, Abramson, 44, likes seeing cars with pro-pet messages, too.

Less pleasant? "I'm sick of seeing the little family lined up," the Queen Village resident said. "I'm not sure why they bother me, but they do. We have five cats and the only thing that occurred to me was to get the five cats."

Aaron Ellsworth is founder and vice president of, the company that unleashed the stick-figure family on America eight years ago. They continue to sell well, he said, with the dog sticker the line's best seller. The human stick family has evolved, and there are now thousands of customization options. Librarian? Soccer player? You're covered. Bee keeper? There's a sticker for that.

"People promote what they're passionate about," said Ellsworth, whose own car carries a customized stick family representing him, his wife, and their five children.

Trends are hard to predict, he said. The success of the stick family was a surprise, as is its continued evolution. Zombie versions are popular right now, he said. As is stick-family backlash. "Nobody cares about your stick figure family," proclaims one decal, featuring a masked stick figure waving a chain saw. Ellsworth's company doesn't make those antifamily stickers, but he also doesn't mind them.

"You know you've arrived when people are putting those on," he said. "It's a sign that we're gaining traction."

Bumper stickers also have many detractors, like Deanna Ward, 24, of Passyunk Square.

"They totally declass your car and bring the value down," Ward said. "Why? Why ruin your car? You can have those feelings, but why do you have to stick them to the car you just spent $20,000 on?"

Those stickers can be hard to remove, too. More than 10 years ago, when Clint Fargason first purchased his car, he stuck a Sleater-Kinney sticker on the bumper. His love for the band has waned, but the sticker is still there, and people still ask him about it.

"This sticker is going to follow me for life," groaned Fargason, of South Philadelphia. "I just keep it there because it was a good time in my life. . . . But I'm done with stickers. I'm 36."

Fargason believes bumper stickers are for younger people (he had not met Montchyk), newly passionate about causes and music: "You feel strongly about something and want to advertise it on your car for some reason."

He and his friend Michael Johnson, 34, looked at another oft-stickered car parked nearby. They began to draw conclusions about the owner based on the stickered Kurt Vonnegut quote, happy sushi, and image of serial killer Dexter from the eponymous TV show. Liberal, Johnson said, maybe hikers or something artsy.

Fargason had more trouble with the variety of messages. "There's so much going on there," he said. "There's New Jersey with the Massachusetts plate, the art and the earth, vacation towns, the chill with a cupcake. . . . I have no idea. They're crazy . . .. Oh my God, is that your car?"

Actually, the gray 1998 Subaru Outback belonged to Joanna Ference, 20, a junior at Drexel University. She walked through the stickers: Vonnegut's her favorite author, turtles represent Florida, Jersey is where she was born, sushi's just for fun . . .

The many destination stickers represent trips she has taken.

"I love to travel and the most fun part is being able to put a new one on, denoting I just went somewhere," she said. "It's like putting a stamp in my passport almost . . . "

Ference, who inherited the car from her grandparents, said she sometimes gets strange looks from people, but that doesn't bother her.

"I've been asked why would you want to cover your car in stickers?" she said. "Why not? It's my car."