It sounds like you are storing URLs without the http:// so they are being interpreted as relative URLs. You just need to do something like this:
link_to micropost.website, "http://#{micropost.website}"
or maybe add a full_url method to that model that adds it if it’s missing.
By the way, you can’t use @micropost in that partial because it doesn’t exist (you only have @microposts or micropost).