So far the only official Oracle blogs have been by some of the senior mangement folks in the Apps division: John Wookey, SVP of Applications Development, Jesper Anderson, SVP of Applications Strategy (formerly from PeopleSoft), and John Schiff, VP and GM of JD Edwards World (link to executive blogs page on Oracle.com). But no other employee blogs are hosted on Oracle.com.
On a lark I entered www.oracle.com/blogs in my browser. I first got redirected to http://www.oracle.com/blogs/index.html and then to http://www.oracle.com/technology/community/opinion/index.html, which happens to be the home page for all links to Oracle technology related blogs.
I am using this very sparse and frankly thin piece of page redirects evidence to surmise that Oracle may come out with a comprehensive blogging infrastructure like hosting support (like a blogs.oracle.com or other URL) and software for blogs. Currently, as people would know, Oracle blogs are hosted on third-party blogging sites like Blogger, Livejournal, or on Orablogs.com. Companies like Sun, Microsoft, and others have a substantial blogging presence by their employees.