It's "bacn," derived from the breakfast meat, an almost alarmingly viral new term for a benign but nonetheless nettlesome category of e-mail. Newsletters you signed up for. Electronic bills. Facebook message notifications. MySpace alerts. The useful but not urgent "middle class of e-mail," as one of the term's inventors phrased it.

It is "e-mail you want. But not right now," according to the official Bacn Web site and, now, a T-shirt.

But what's more remarkable than the sudden and seemingly necessary existence of the term is its rapid dissemination.

It was invented on a late-August Saturday afternoon in Pittsburgh and in less than a week, more than 500 blog posts had been written about the term, according to the Technorati blog-tracking service.

There was already an incipient bacn backlash movement, with people complaining about whether the term was apt -- is bacon just too tasty a food to truly describe this category of e-mail? Major media were beginning to cover it, and Boing Boing, a leading site tracking Web culture, wrote about the term's viral spread as more proof of "the ridiculous power of the Internet."

But the making of bacn speaks also to the continued frustrations most of us have with e-mail, and, mostly, to the simple, old-school power of naming something well.

"The minute I heard it, it just made perfect sense," said Chris Brogan, a co-founder of the PodCamp Web conferences, the 2007 Pittsburgh edition of which spawned bacn.

Though it was coined by Web 2.0 types -- people who use the Twitter service, for instance, to constantly broadcast their thoughts and doings -- it also works for more traditional e-mail users.

"I think it's quite clever. It's a very useful distinction," said Will Schwalbe, a co-author of the recent "Send: The Essential Guide to Email for Office and Home." Bacn works because it is, most commenters agree, a strong name, but a big part of its spread is because of the context in which it was created.

At the registration desk for PodCast Pittsburgh 2, about a half-dozen attendees and show workers were talking about their overwhelmed e-mail in-boxes.

"Somebody got a Facebook friend request. Somebody else got a Twitter notification," said Tommy Vallier, who works in Web development and new media in Kingston, Ontario. The group realized that, rather than old-fashioned spam, "all of these things are the majority of our e-mails," he said.

And the group decided to give this category a name.

"Somebody hollered out the name bacon, kind of as a joke," a play on "spam," Vallier said. But it rung bells instantly.

"We kind of realized what we stumbled upon and how legit the issue really was," said Jesse Hambley, a Pittsburgh Web designer who runs the bacn site with Vallier. "Within 15 minutes we had a whole marketing idea on how to spread it, including setting up a Bacn Information Session" on Sunday at the conference.