Isn't the marketing more about building your network (and/or community, however you choose to see it)? I was aghast when I joined and saw the new posts page - how on earth was I going to wade through that to find any posts of value to me? But then I took more of the same approach I would take to going in a pub - I said hello to someone I knew, had a look at who was joining in the conversation in his posts, followed a couple of them and where I had something to say, joining the conversation on their posts. Only been here three days, so I don't know how it's going to pan out, but I would guess some will become a core part of the network, some more peripheral and some (probably the vast majority) will come and go. I think the received wisdom is a ratio of 1:9:99.