The number of online adults to use classified ads websites, such as Craigslist, has more than doubled since 2005.

The number of online adults who have used online classified ads has more than doubled in the past four years. Almost half (49%) of internet users say they have ever used online classified sites, compared with 22% of online adults who had done so in 2005.

On any given day about a tenth of internet users (9%) visit online classified sites, up from 4% in 2005.

These are the main findings of an April 2009 survey by the Pew Research Center’s Internet & American Life Project survey. They highlight the growing importance of such sites to internet users and reflect the changes in the audience for classified ads – both those who place them and those who make purchases – that have devastated a key revenue source for traditional newspapers.

The figures also underscore the growing social role of online classified ads. On May 13, Craigslist eliminated the controversial “erotic services” section of its site and said it would manually review every ad posted in a new “adult services” section it had created. The move came after a Boston medical student was charged with killing a masseuse he had found on the erotic services section of Craigslist.

In the world of online classified advertising, Craigslist is by far the most used website in the United States. In March 2009, classified sites averaged 53.8 million unique visitors, up 7% from February.1 Craigslist had 42.2 million unique visitors in the month of March.2 The free, no-frills, user-generated and self-policing classified ads site has grown tremendously since its start in 1996 in San Francisco. As of April 2009, Craigslist had established itself in over 500 cities across 50 different countries.3 Some other online classified sites include Gumtree (primarily UK) and Kijiji (worldwide).

Classified ads sites are a one-stop-“shop” for everything from jobs to apartments to furniture to movers to puppies. However, users don’t buy anything directly on classified websites – they use the sites to set up meetings, and transactions are conducted in person or by mail – a characteristic which separates online classifieds from auction or shopping websites like eBay and Amazon.

Age is a significant factor in online classifieds use.

Free online classifieds sites like Craigslist are tremendously popular with  young adults moving to new cities, looking for jobs, or trying to find inexpensive goods or roommates. Internet users ages 25-44 are significantly more likely than any other age group – including 18-24 year olds – to use classified ads. Fully 62% of online 25-34 year olds and 57% of 35-44 year olds use online classified ads, compared with 49% of online 18-24 year olds and 48% of online 45-54 year olds.

Internet users 55 years old and older are significantly less likely than younger age groups to use online classifieds. Just over a third (35%) of online 55-64 year olds use classified sites, while about a quarter (26%) of internet users 65 years old and older do so.

On a typical day, 18-44 year old internet users are also slightly more likely than online adults 55 and older to use classified sites.

College graduates and higher income-earners as well as urban and suburban internet users are more likely than their counterparts to use online classified ads.

Online adults living in households with incomes of $50,000 or more a year are significantly more likely than lower earners to visit and use classified ads sites. More than half (56%) of higher income internet users use sites like Craigslist, compared with 47% of those making $30,000-$49,999 and 42% of those making less than $30,000 a year.  In addition, online adults making $50,000 or more are more than twice as likely as those earning less than $30,000 a year to use online classified ads on a typical day.

Similarly, college graduates are significantly more likely than online adults with no college education to use online classified ads. Fully 54% of online college graduates use classified ads sites, while 45% of online adults with a high school degree and 40% of online adults with no high school education use these types of websites. However, college graduates are no more likely than those with less education to use online classified ads on a typical day.

Urban and suburban residents are also significantly more likely than rural internet users to use online classified ads. Some 47% of both urban and suburban internet users utilize sites like Craigslist, compared with 32% of rural internet users. Online rural adults are also much less likely to use these sites on a typical day: one in ten (10%) urban and suburban internet users use online classifieds, while just 4% of rural adults do so.

While women and men are equally likely to visit online classified ads sites, men (12%) are slightly more likely than women (7%) to use these sites on a typical day.

Demographics of classified ad users have changed little over time, though younger age groups grew even more likely than older groups to use classified ad websites.

Over the past four years, the demographic makeup of online classified users changed very little. The percentages of demographic groups using online classifieds grew at a rate that mirrors the growth of the total online population using these sites: the percentage of all internet users to utilize classified sites grew 27 percentage points from 2005 to 2009, while most other demographic groups’ growth ranged from 25 to 29 percentage points.

The exception to this pattern involves different generational use of classified sites. Online 18-29 year olds saw a 30 percentage-point increase in their use of online classified ads, and 30-49 year old internet users marked a 32 point increase in online classifieds use. On the other hand, internet users ages 50-64 saw a 21 point increase, and online seniors (age 65+) saw the smallest increase overall: 13 percentage points.