"The NIPC and Richard Clarke do have an excellent track record of warning about cyberattacks and cyber-badness that is often only visible to them," Smith said.

Such warnings of invisible menaces include the NIPC's 1999 alert warning that every nation whose name began with the letter "I" would target American computer systems on Jan. 1, 2000.

That warning was followed by another prediction of worldwide hack attacks on Jan. 1, 2001, and the impending fall of the Internet due to the Code Red worm last summer.

Since the NIPC doesn't have a sterling reputation among many security experts, more time and energy was devoted to attempts to figure out what might have induced them to issue their latest alert rather than hardening websites and systems.

Some believe that the latest NIPC warning may have been a rather desperate move made in the hopes of gaining publicity and proving the agency's value.

According to Rob Rosenberger, also of vMyths, it appears the CERT Coordination Center, a federally funded research lab focused on computer security, has decided to sever what Rosenberger described as its "co-dependent relationship" with the NIPC.

Rosenberger mentioned this rumor at his keynote speech Tuesday at CERT's annual computer security conference.

"NIPC believes they need CERT's technical prowess if they want to survive politically. I tend to agree," Rosenberger said. "But if CERT doesn't want to continue the relationship, I imagine they'll suffer the classic symptoms of a co-dependent breakup. I can imagine NIPC wailing how the relationship must continue in order to save the world from future cyber-terrorism. 'Honey, I swear, just give me one more chance, I need you'...."

"So who knows?" Rosenberger added. "The NIPC's latest PR move could be a manifestation of a co-dependent breakup in progress."

Whatever motivated Monday's warning, security experts believe that the NIPC shouldn't issue public alerts about issues that concern Web and systems administrators.

"It seems to me that warnings of attacks against the Internet infrastructure and large websites don't really require a public announcement," said security researcher Richard Smith. "A private e-mail list for system administrators should be good enough."