Prepaid wireless services are continuing their soaring growth, according to data from ComScore. Web site visits and search referral activity for the six leading prepaid providers grew 37% year over year, according to the online metrics research firm.

MyCricket.com and BoostMobile.com paced the category with gains of 107% and 105%, respectively. Both providers started from a relatively small user base and grew rapidly.

ComScore noted that the gains occurred "during the economic downturn," but consumers are turning to prepaid plans for reasons other than only the poor economy. With handset life cycles shortening, some consumers are hedging their bets on devices becoming obsolete by using prepaid plans to avoid signing up for two-year service plans.

In addition to the hockey-stick growth of MyCricket and BoostMobile, rapid growth by MetroPCS and Net10.com was also recorded. Site traffic to MetroPCS grew 63% and Net10.com tacked on 37%.

The two largest prepaid service providers -- VirginMobileUSA.com and TracFone.com -- posted single-digit percentage declines.

While prepaid service providers are muscling in on the turf of established wireless service providers, their combined percentage of online visits and search referral activity reached just slightly over 4% of the total U.S. Internet audience.

In its report released Wednesday, ComScore found a growing interest in prepaid services among consumers between 35 and 64 years old, even though prepaid vendors target their marketing messages to the youth market. A majority of Net10 (60.3%) and TracFone (58.7%) visitors were from that older age segment. ComScore noted that the results could be skewed by older parents acquiring handsets for their children.

"Even for sites where the majority of visitors were under 35 years of age, such as BoostMobile.com and MetroPCS.com, 35-64 year olds still comprised at least 40% of visitors," according to the ComScore report.

InformationWeek has published an in-depth report on smartphone security. Download the report here (registration required).