I haven't read both articles thoroughly, but two quotes from the articles will answer your questions: Blog post: "Project Infinite will enable users to seamles

I haven't read both articles thoroughly, but two quotes from the articles will answer your questions: Blog post: "Project Infinite will enable users to seamlessly and securely access all their Dropbox files from the desktop, regardless of how much space they have available on their hard drives." This post: "Dropbox today released Smart Sync..." So the blog post was a demo about feature in the future, while this article says it is already released.