By positioning herself as a "girl", I think of her as a girl first, and a developer second. What qualities do I associate with girls? Not the qualities I look for in a programming blogger. Is that prejudice? I guess so.
I clicked the link because it had a catchy title, not because it was from a site "girldeveloper". That I'm not even thinking about the content of the post anymore speaks volumes.
Women are a significant minority in software development. This in itself means that a woman's experience of the field I work in every day must be different to mine. You're more likely to learn something new from someone looking at the same things you do from a different perspective than you are from someone who shares your POV and is more likely to just tell you things you already know.
The blog still has to be interesting, but "girldeveloper" is as good a hook as any.
I did: "I think" "I associate" "I look" "I clicked" "I'm not"