I think that a blog is a potentially great way to cover some areas of LLVM that we're lacking in the community:
1. A place to describe cool new features and enhancements (which we can link to from the release notes). 2. Description of the motivation behind major API changes. 3. Higher level algorithmic descriptions. 4. A place for people to write about how they're *using* LLVM 5. a place for expanded information like version of http://llvm.org/ProjectsWithLLVM/ and http://llvm.org/Users.html 6. Updates on major accomplishments for sub-projects that are still in development (clang, dragonegg, MC, etc).
More than anything else, while LLVM is a highly dynamic project, our web page isn't. I'm hoping to add sidebars to the llvm.org and clang.llvm.org web page that will show the blog feeds to get some of this information more visible.
In any case, for it to be successful, we need writers! If you'd like to write an entry, please let me know. The only request that I have is that the entries be about things that you have *done* and are checked in, not about crazy ideas. Once the crazy idea manifests as something great, it can show up on the blog :)