Oskar Stål has joined Spotify as its new CTO after the departure of the original CTO Andreas Ehn, who left to pursue his own startup. I guess people slightly forget that next year Spotify is actually going to be 4 years old, even though it only launched publicly at the end of last year. (Long time in private beta).

Stål comes from the mobile transaction company mBlox, where he’s been for the last eight years, growing from a five-person start-up into a global business.

By hiring a CTO with deep mobile experience it’s clear Spotify sees the mobile as the key supporting plank in its structure. Last night I spoke to a Spotify contact who told me that since they launched the Symbian version of Spotify, the service has “gone crazy.” Make of that what you will. Symbian, as a platform used by Nokia’s non-smartphones, is of course a great deal more mainstream, especially in Europe, than the iPhone or Android.