This news about the Dixie Chicks should make marketing and PR folks - and blog triumphalists - look up and take notice. Their new album has been selling very well online, but they are having difficulty filling venues for concerts:

Initial ticket sales for the Dixie Chicks' upcoming tour are far below expectations and several dates will likely be canceled or postoned.

Ticket counts for the 20-plus arena shows that went on sale last weekend were averaging 5,000-6,000 per show in major markets and less in secondaries, according to sources contacted by Billboard. Venue capacities on the tour generally top 15,000.

In contrast, the band's new album, "Taking the Long Way," sold 526,000 units in its first week, according to Nielsen Soundscan, the third-largest sales week of 2006. The album logged a second week in the period ended June 4, according to sales data issued Wednesday.

One of the interesting aspects of the net is the "long tail". Regardless of what hobby or profession you are in, the net - especially the blogosphere - makes it easy to find like minded individuals and form a community. That community might be quite large, and as with the album sales cited above, be commercially successful. That doesn't necessarily mean that you've got a mass audience in the classic mass marketing sense of the word, however.

What the Dixie Chicks are learning about first hand is the existence of the long tail, and what it does and doesn't mean. Here's a more personal example. On a weekly basis, I have about 20,000 readers. Does that mean I can promote a Smalltalk conference and expect 20,000 attendees? Based on the attendance in Toronto (which was good, but in the hundreds, not thousands), clearly not. My readers are in the long tail. Not all of them are Smalltalkers, and, of the ones who are, not all of them will go to a conference (for a variety of reasons).

The net makes it easy to mistake a large online community for a similarly large offline community. The two aren't the same. Online, geographic space is irrelevant. Offline, it's not. That has relevance for artists, marketers, and politicians, just to state three obvious examples. For the next little while, I expect to see a number of marketing errors based on this.