Review Open-Source Software
On Code Review, asking to review other people's code is normally off-topic.1 However, a blog is not subject to the same restrictions.
Unlike most answers on Code Review, which are directed to a small audience, a technical review of widely used software would be of general interest. If we blog about a security, correctness, or performance bug, that could drive a lot of traffic to the site and illustrate the value that Code Review can provide to anyone's code.
Each post would focus on an interesting portion of a project, e.g. the authentication system in WordPress. (I've looked there, and it's not pretty!)
1 There is a possible loophole for open-source code. Anyone could claim to be a maintainer of a fork of an open-source project.