Digital books on tape can be addictive. I've had an on-again, off-again love affair with the format for years, and the concept is at least partly responsible for my poetry spree in April. National Poetry Month snuck up on me in the middle of a 24-part series on poetry appreciation.

So I'm glad to see that Audible (NASDAQ:ADBL) is doing well. From an egotistical point of view, that company's success translates into more audio-book goodness for me, as publishers become convinced of the format's economic viability.

Audible has landed a few sweet distribution deals over the years. There's XM Satellite Radio (NASDAQ:XMSR), online retailing powerhouse (NASDAQ:AMZN), and the jewel in Audible's tiara, Apple's (NASDAQ:AAPL) iTunes. CEO Donald Katz says that Apple tends to do the marketing for Audible for free, bringing in most of the new customer signings.

Audible's subscription growth is remarkably consistent, hovering around 70,000 new customers per quarter for about a year. Monthly churn -- a measurement of the number of existing subscribers lost in a given period -- was a very respectable 3.0% in the just-completed quarter. That's up from 2.5% last quarter, but still lower than other well-respected and customer-focused subscription services. Netflix (NASDAQ:NFLX) shows about a 4% monthly churn rate, but TiVo (NASDAQ:TIVO) looks nearly untouchable at a piddling 1.2%.

The low churn rate is respectable in itself, but looks even better when you factor in a recent push for higher-priced subscription plans. Only a very satisfied clientele would convert to 50% higher prices, even if the pricier plans do have a few extra benefits.

So there's price elasticity and faithful customers, in a market with very few credible alternatives. I mean, there are plenty of audio books out there, but you can't download them, slap 'em onto your iPod, and go jogging in 10 minutes' time. At least in the American market, convenience is king.

A couple of years ago, when I was but a mere pup of a Fool, and many moons away from my own contributions here, our Rule Breakers newsletter hinted at the next pick coming from the subscription entertainment sector, and I thought Audible had to be it. Instead, my compadre Rick Munarriz picked XM Satellite Radio. Audible still isn't on that scorecard (and XM has dropped off it), but this stock -- volatile though it may be -- surely fits the iconoclastic bill.

Further Foolishness:

Amazon, Netflix, and TiVo are all current Motley Fool Stock Advisor recommendations. Read all about the Gardner brothers' entertainment keiretsu with a free 30-day trial pass to our flagship newsletter.

Fool contributor Anders Bylund is a Netflix shareholder but holds no other position in any of the companies discussed here. You can check out Anders' holdings if you like, and Foolish disclosure is soothingly sonorous even at low bitrates.