A "Post" is a short content format or 280-character limit. Post can attach a maximum of 4 photos. Post will show link preview if there is no photo attached.
A "Blog" is a long content format without character and photo limit. In the future, the Blogger can design the typography; Header, Bold, Italic, Underline, Link and attach photos for better read experience.
A "Recast" is to share content without a caption to your timeline.
A "Quote cast" is to share content with caption to your timeline. Quote cast is limit to 280-characters and no photo attachment allowed.
When you do quote cast, the content reach rewards will be credited to the original creator. But you still can do content farming and quote cast to earn content farming rewards from the quoted content.