Today I saw an article about a $1.9B datacenter farm being built in Scotland, and it brought home to me just how many new datacenters are going up right now. Terramark just announced its NAP of the Capital Region, Savvis, Equinix, and Internap are all building out large amounts of colocation space. The credit markets may not be available to the rest of us, but if you build datacenters you can pretty much raise what you want.
And it's not just the bigger colo providers, it's the smaller ones also. Internap is building out, so is Colo4Dallas, and numerous others. And of course we frequently hear about Google and Microsoft building vast datacenters all over the world. All these facilities are going to be filled with servers. Piles and piles of servers - and remember servers get more powerful with time as quickly as traffic grows (Moore's Law and all that). You don't generally need more colo space for normal internet growth, you just need to upgrade the servers to the next chips from Intel or AMD or Sun. While we see 50% annual traffic increases, the industry is planning for truly massive internet growth.
I suppose now we had better hope it really happens, because if it doesn't there's going to be another colocation glut.