At present, all of the sites share a common blog (accessible via blog.stackoverflow.com or blog.stackexchange.com, or following the link in the footer of the SO/SU/meta/careers/apps/area51) except for SF.
Surely, since the SF blog is a form of meta, discussing the infrastucture and admin behind the sites, it would sit well with the main, common blog, which discusses things such as how the software is implemented, who works to produce the sites and what changes are being made or being planned, which are also similar forms of meta.
I'm not suggesting that the two need to be combined because of a lack of content, and I'm curious as to the "exciting new announcements" mentioned by Jeff in his answer to this question. Obviously if these announcements mean that the subject of the SF blog will change direction to cover SysAdmin stuff en general, and not focus on the specifics applied to our sites, then there is little reason to merge it, and doing so would bloat the main blog, but I don't think that we need to be concerned about SO users not wanting to read SF-type articles on the main blog. The main blog at present is not for SO or SU or SE users - it's mostly for people interested in the meta behind all these sites.