[matsiyatzy]

I believe the model they're using is called Pareto/NBD and is fleshed out a bit more here:

http://marketing.wharton.upenn.edu/documents/research/Fader_...

[aaronjg]

Indeed. Here is the original paper if you are interested in more details.

http://www.jstor.org/pss/2631608

[matsiyatzy]

Thanks! Interesting articles by the way.