As an RL marketer I have recommended SL to clients including Smirnoff and Unilever and MTV. It is a tough battle as demographics are so untrackable.
My company actually brought clients from Guiness and Schick in-world with a holiday party in 2006. (Video at www.seeloweindusties.com) I have been a vocal proponent of virtual worlds.
That will end. Not because I am not a believer in virtual worlds and branding, but because I do not trust Linden Labs.
It isn't the money thing frankly, it is the "bully boy" tactics they employ lauding over this brilliant world that was Phililip Rosens vision and has now been hijacked by the "money men."
Sadly, true Virtual World vision will be left to the next man or woman to create. It is a shame that Mr. Rosen's legacy has been so tarnished.
I hope that SL will not taint peoples belief in what Virtual Worlds can be. This will always just live as the worst example of what they can become.