(CNN) -- Every time her cell phone rings, Christy Harness thinks of her husband.
More consumers download ringtones to their cell phones than full-length songs.
The 34-year-old native of Jackson County, Georgia, set her ringtone to Sugarland's "All I Wanna Do," a song that, she says, perfectly expresses the way she feels about him.
"I kind of put myself in [the singer's] place because ... she's in love with this guy. If he's not around, she misses him. Basically, I think the song relates to me and [my husband] and our relationship," Harness said.
These days, ringtones do much more than alert mobile phone users of a call. Ringtones seem to have become vital fashion statements, a way for people to showcase their personalities and even their feelings about who is calling.
According to a 2008 study by Ipsos MediaCT, a marketing research company, approximately one-third of mobile phone users download ringtones, and about 40 percent of users change their ringtones frequently.
Ipsos research shows that ringtones are the most common type of mobile music content downloaded by users, compared to full-length songs and ringback tones, tones that replace the typical ringing signal heard by the caller.
"I find regular ringtones kind of dull, so I wanted something exciting," said Gordy King, a 51-year-old from Salt Lake City, Utah. King said he gets a kick out of annoying his mostly Republican co-workers with his Barack Obama ringtones, even playing them over the intercom at the electrical supply warehouse where he works.
"It's fake news people saying 'Barack Obama has won the election,' " he said. "I really like Barack Obama. I think [my ringtone] probably says that I'm nonconventional and it says I lean a little more liberal. I don't know anyone else who has that ringtone."
Using a ringtone creator application on Facebook, King said he also makes his own ringtones by downloading sound files onto his computer and editing them to be shorter and louder or softer.
Donald Kaplan found a perfect fit with his ringtone choice. Kaplan, of New York, changed his ringtones often before finally settling on the theme song from "The Good, The Bad, and The Ugly."
"I'm thinking of sticking with it. I notice that when people hear my phone ring they get amused ... I think that people really connect with that movie," Kaplan said.
But that's not always the case. Kaplan said one of his co-workers wasn't exactly pleased with the ringtone. The co-worker sent a mass e-mail to the office, telling everyone to keep their cell phones on silent.
"The ringtone drove him crazy and he tried to be tactful but I knew that [the e-mail] was directed specifically to me," Kaplan said. "I could tell that this particular ringtone just drove him up the wall ... just the repetition of the sound."
For some, one ringtone simply isn't enough. Many mobile phone users set specific tones to specific people so that the tones act as audible caller IDs.
"I group people," said Natasha Khan, a 26-year-old from McLean, Virginia. "I group all my best girlfriends together, the people I don't want to talk to together, work contacts together, and family together."
Khan said when her best friends call she hears "Girls Just Wanna Have Fun," by Cyndi Lauper, and when she gets a call from people she doesn't particularly like, her phone rings "Bugaboo" by Destiny's Child. "Bugaboo," about a woman irritated by a male caller, contains such lines as, "It's not hot that you be callin' me."
"The 'Bugaboo' ringtone has gotten me in trouble," Khan said with a laugh. "This guy -- I forgot that he was on that list and I told him I needed his number and he said, 'Oh, I'll call you' and he realized he was on the list."
Customizing a phone with multiple ringtones can be expensive. Depending on the wireless carrier or the service plan, ringtones cost anywhere from $0.99 to $2.99. That may not deter cell phone users. Analysts at Screen Digest, a UK-based firm covering global media markets, predicted that mobile music sales will double from $1.6 billion in 2008 to $3.2 billion in 2012.
But there are also free ways to get ringtones, like the ringtone creator application on Facebook -- one of several ringtone applications on the social-networking Web site -- that make setting ringtones all the more appealing.
"The ringtone creator was fun," said King. "No matter how big or little the song or sound effect ... you could select a snippet and edit it."
Many mobile phone users like to be creative and have fun with their ringtones, and their ringtone choice can reveal much about their personalities.
Khan's default ringtone, she said, is typically an upbeat dance song like her current one, "Forever" by Chris Brown.
"I think the day can be so mundane and work can bog you down, so I like any chance I can get to get some joy," Khan said. "It's just a break in the day to feel good randomly."
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