Well, seems the Lindens are clearing their backlog and delivering today (!) about 300 islands.
Let's calculate a little. For normal users (non educational) reserving a region costs 1.675 US$ and the monthly maintenance fee for an island is 295 US$.
So alone on reserving costs 300 new arriving islands mean: 300 islands * 1.675 US$ = 502.500 US$ income for Lindenlabs. Of course not all of it profit, since they're using these fees to pay the server hardware, plain and simple, but surely are still making some profit with it.
Then 300 islands * 295 US$ maintenance fee per month and per island = 88.500 US$ income on maintenance fees per month with these islands. Most are surely used to pay the staff and the location, but that's where the real profit comes from for Lindenlab.
So - not bad, hu?
Let's be very happy they are doing good. The profits will be used to invest in better software and a better experience in SL. They need lot's of funds to be able to fix the lag problem, and they really need to fix that to ensure growth. SL could become the next (3D) web, but only if it can scale up that big (without just keeping adding one island per 100 avatars :-p ).
I'm very happy so far they're getting some income. Hopefully they're able to generate finally some profit, too.
But let's face it: I'm in SL since about half a year now. It is not as much fun ago than it was back in September, because the online player count grows day by day and there are still unfixed issues, mainly the almighty lag many of us experience.
So if they want to grow also a fix of this should be top priority, this means adding more bandwidth, I guess and some other changes to the technical infrastructure.
Because if the issues continue to go on, sooner or later the word will spread around and then people are going perhaps to avoid buying islands. When you've got a bad image it's very hard to turn it around, again. So - they better should fix it and fix it soon.