And a transcription of the full interview you can find on Jo Yardley's Blog.
I am actually quite impressed about the figures he gave:
The transactions volume within SL is about a half billion USD a year, about 400,000 sign-ups and one Million people active in SL per month.
Despite the decreasing number of sims he describes the economy in SL as "robust", which is rather good news. Also he talks in length about the creative potential of the community, performance improvements (something he did admit which was neglected by LL for years) and his astonishment that SL is around for 10 years now.