Business in Second Life

At Silicon.com there was a post related to what we saw in class yesterday - business in Second Life. They say that

Business[es are] still experimenting in Second Life but confusion over measuring virtual world success.

I am also curious how they will measure the success or failure of advertising/marketing on Second Life. They have virtual compnay islands, so they might count visits to their islands, but it would be difficult to see if it leads to actual purchase. Since many businesses have been in Second Life for a while, they must believe there is a positive effect. Or as the article says:

Businesses are unsure about the benefits of using Second Life with many still just experimenting with the virtual world to discover its true value.

The companies may still be experimenting with the presence on a virtual world. If it works, Second Life may expect to earn a lot from advertising from eager advertisers to join the virtual advertising.