DETROIT (AP) — Millions of fingers scurrying over mobile electronic devices might have paused momentarily this week as news emerged of a trove of text messages containing flirty, sometimes sexually explicit chat between Mayor Kwame Kilpatrick and a top aide.

Even those engaging in more wholesome dialogue would be wise to wonder: Do such messages disappear into the ether or are they permanently logged for potential retrieval?

The answer is largely the former for standard text-messaging technology used by consumers. But the communications devices used by Kilpatrick and Chief of Staff Christine Beatty employ less-fleeting technology.

"I think people can feel comfortable we're not storing information that can later be used against them," Verizon Wireless spokeswoman Erica Sevilla said. "Unless you have something stored on your phone or on a recipients' phone, it does not stay on our network for a long period."

Other wireless carriers employ similar technology. AT&T Inc., for instance, said it keeps text messages for up to 72 hours until delivery is successful. Spokesman Howard Riefs said if it can't be delivered, it's removed from the system and can't be accessed or retrieved.

At issue is whether the messages between Kilpatrick and Beatty constitute perjury.

The pair testified last summer in a whistleblower trial that arose from a lawsuit filed by two police officers. The officers alleged they were fired for investigating claims from two former bodyguards that the mayor used his security unit to cover up extramarital affairs.

Kilpatrick and Beatty denied any sexual or romantic ties in 2002 and 2003. But the Detroit Free Press said in a story published Thursday that it examined 14,000 text messages on Beatty's city-issued pager from those years and found many examples of such ties.

The city's text messaging service is provided by Mississippi-based wireless company SkyTel.

Roger Pondel, a spokesman for SkyTel's parent company Bell Industries Inc., declined comment Friday.

SkyTel's devices employ a technology called Narrowband PCS, including two-way paging, that "rose and fell" in the mid-1990s, according to David Chamberlain, a wireless analyst with Scottsdale, Ariz.-based In-Stat.

Chamberlain said SkyTel's device is more akin to e-mail than to text-messaging, and messages are stored. While mainstream technology has since moved to SMS or Short Message Service technology, some corporations and governments have stayed with wireless services like SkyTel.

"It was going to put mobile messaging in the hands of lots of people," Chamberlain said. "(But) it was so poorly differentiated from text messaging. It required people essentially to have a second, very expensive message-only account."

Of course, such contracts with corporations and governments also include language that the communications will be stored for legal reasons. Chamberlain said users of any technology should be aware of that when using company-issued devices of any kind.

"Our company made it very clear," he said. "There's absolutely no expectation of privacy with phones, e-mails, text messages, or computers."

While people may feel comfort knowing their text messages aren't permanently stored, that doesn't mean that they should let their guards down when it comes to electronic communications, said a spokeswoman for an online privacy advocacy organization.

"The whole concept of data retention by third parties ... is going to be the big privacy question over the next couple of decades," Rebecca Jeschke of the San Francisco-based Electronic Frontier Foundation.

"We trust so much of our communications and thoughts, even, to these third parties who are capturing this information and storing it in various ways. It's time for us to think about it."