WordPress Posts are basically blog type posts which can be created and interact with categories and tags.

• Posts consists of news or useful updates about certain topics
• Posts are listed in reverse chronological order and can be tagged, categorized and even archived.
• Your WordPress posts can interact with RSS so when someone subscribes to your RSS feed, your posts will be the content that’s delivered to them.
• Think of the posts at the news portion of your site. They’re dynamic and constantly changing the content your end users sees.