50 days: worried!

Skype reached 9 million concurrent users online on January 29. We are now 50 days later, and the counter is only at about 9.250.000 concurrent users online.

If we suppose a linear growth, we should reach 10 million concurrent users online within 150 days.

Quite disappointing. Edited: last year (2006) Skype grew from 5 to 6 million concurrent users online between January 20 and March 27. This was in a time span of 66 days!

I see two possible reasons, but these are pure guesses:

1. SkypePro is a failure, and a lot of customers try other cheaper solutions like Gizmo, Jajah or VoIPstunt
2. The growth in rich countries has reached some point of saturation, because most of those people interested in the features of Skype already use Skype or have at least tried it.