That means government investigators or civil practice lawyers searching for damaging evidence are increasingly likely to ask for those messages.

So far, both government and corporate attorneys have avoided the issue of voice mail files as evidence.

But compliance and legal experts are increasingly worried that it will become the next major minefield in corporate litigation.

Some companies pin their hopes on expectations that judges will deem it "unreasonable" to ask businesses to retain the thousands of voice mails recorded daily.

Click here to read about the ways that CIOs neglect compliance best practices.

Indeed, companies are not expected to forever retain every record they generate.

Still, Michele Lange, a staff attorney specializing in electronic discovery for security firm Kroll Ontrack Inc., said lawyers and company executives are nervously awaiting the court case that will "blow the door off" the voice mail topic.

Such a case would entail a precedent-creating judicial opinion approving or denying a request for a company to produce all its discoverable voice mails.

So, if this is the calm before the storm, should companies make a point of archiving and otherwise nurturing the myriad voice messages they receive?

"Maybe," is the bottom-line advice of Steven Bennett, an attorney who writes about electronic discovery.

"We should think about what we're doing," he said. "The question is, are you going to think about it in advance or will you wait until something happens in the course of litigation and then try to make up a system after the fact?"

Bennett and other electronic evidence experts have offered that opinion for several years now, but many companies are still treating voice mail as a disposable form of communication.

Next page: There's a gap in the rules for voice mail.