Network effects are also critical for deployment. People pick up the things that their friends use. This is all fine and well if everyone can get access to the same platform, but when that's not the case, new problems emerge. We're all developing nice new social technologies for the mobile phone. And people even want those technologies. But they aren't taking off. Why? There are no cluster effects. If you use IE and I use Firefox, we can still both get to Facebook. If you use Windows Mobile and I use an iPhone or you're on Verizon and I'm on AT&T, the chances of us being able to do the same things with our devices are pretty limited, especially when you take into account the limited nature of data plans. We can't role out cool new technologies if we can't get cluster effects. We don't just need network effects to get things to spread; we also need to think in terms of complete clusters. And we need to design with this in mind.
In January Fred Wilson wrote about super cheap CPMs. His prediction for 2009 was that "display advertising will get so cheap and the tools to target it will get so good that it will be shown that it can outperform search." It's an interesting one. When the media space gets cheap enough, it doesn't really matter what the click-through rate or anything else is. That's why spam works after all (some incredibly small fraction of those spammed has to actually act on it for the ROI to work out). Of course this kind of flies in the face of everything I said before, but hey, who's counting? The issue of course with super low CPMs is that it's hard to make a lot of money off them if you're a publisher (well that and really crappy banner ads hurt your brand as a publisher). But anyway, it's a different way of thinking about online advertising.
PR is the strategic crafting of your story. It's the focused examination of your interactions and tactics and products and pricing that, when combined, determine what and how people talk about you.