Yes.

If an ArXiv paper beats you, you are still beaten. If a blog post beats you, you are still beaten.

Peer reviewed material does not have a special status within science. Some important results are in somebody's BSc thesis, or on website somewhere, or in some mathematicians talk, which somebody wrote up a lecture note about. That doesn't mean that they can just be ignored. This can be true even for big results. For example, the proof of Poincaré conjecture were simply TeXed up by the mathematician who proved it and put in his university webpage.