Above is a very SAFE linking strategy that's built for the long term.
The thing to note is that the "zipper effect" is how the typical web 2.0 link wheel is broken up with independent IPs.
Check out the gray arrows for this and see how they zigzag from hosting IP to web 2.0 site back to host back to 2.0 site. By adding these unique IPs to the "zipper", you're breaking up easily detected link wheel IP footprints.
The red arrows are another zipper, but they "skip" a few notches in the zipper. The point is to link two to properties, while avoiding a "link exchange".
Also, this is a GENERAL THEORY. Don't get caught up in perfection. It's OK to sometimes link a 2.0 site to another and to link a host to another. Just break up the patterns of a typical link wheel and don't chain together a lot of consecutive 2.0 sites.