Agreed. Right now this is technically "Search for static BLOG sites". If you had the ability to scan simple HTML files as well, it could work for any HTML site, even if it weren't a blog site (or another site type that has a time-ordered list of posts in an RSS feed).
We're definitely looking into this and hope to find a clean solution soon. We started by indexing RSS since it was what we needed and since it was _way_ simpler to implement for a first version. Stay tuned! :)