It's about the "cliques"
...not "clicks". Advataring is not about open rates, click throughs, or even conversions. It is about creating a community around a brand that is influential over the sentiment of a brand for each and every member of the community. Avatars are social in nature, they communicate via various mediums, but basically they are about interacting and communicating with the virtual world they reside in, which includes other avatars. Thus, to market to them, you must treat them as communities, not as individuals. In doing so, you will effectively influence the community to immerse itself in a brand, your brand.
There is a mantra by a well-known advertising company that goes something like this "The more time a person spends with your brand, the more likely they are to spend money with your brand." This defines Second Life in that we are not trying to drive clicks or conversion, rather we are driving immersion by communities into a brand. A person that is immersed in a community will spend time with that community. If said community is immersed in a brand, then members of that community will spend time around the brand which will increase the likelihood they spend money with that brand, either in first or second life.
Thus if x = a user, y = a community, and z= a brand, if x is a subset of y and y is a subset of z, then x must be a subset of z (I just made that up, smile).