Corporate blogging is -never mind the hype- still not a common thing. How to get blogging from an exception to a way of work shared by your workforce?
The way to go is like anything else you want to implement in your organization. Start with the early adopters, make them special and let them pave the way. When the early majority kicks in, start cheering towards groups that perform the best practices. Finally, make it a (moral) obligation.
Get blogging into your culture by rewarding early adaptors and oblige laggards.