Following up on Jim's Q1-2007 Is Skype's First Profitable Quarter, I thought I'd see if I there was more to it.  

Skype calling didn't grow in Q1-20070.

Skype-to-Skype calling didn't grow this quarter, despite 25 million new accounts. Isn't this a churn indicator? For each minute a new user called, someone else chose not to Skype for a minute. This could be seasonal: Q1 2006 was also close to flat growth.

And as you can see in the chart below, Skype's retiring of free SkypeOut plans killed SkypeOut growth for the same period. This is clearly not seasonal.

Paid calls are a bigger part of the mix.

Paid calls doubled their share of all Skype calls in six quarters. Only 1 in 11 calls was paid at the end of 2005 but 1 in 6 was paid for at the beginning of 2007. National calling plans (convenience, predictability) fed the increased use of SkypeOut.

No more than 60% of accounts are active.

The combination of fee and free minutes served rose along with the number of accounts. We can crudely guess the number of inactive accounts. First, let's assume active accounts use the same number of minutes each quarter. But you can see the minutes consumed divided into all accounts fell from 76 to 47 minutes per account per quarter. That means that at least 40% of all accounts are inactive.

Is that fallow rate accurate? We don't know and Skype isn't saying. It's probably higher. The number should rise as more people get separate accounts for work and home.

Is that churn rate good?