Popular on Instagram, and other social networks, BAE is commonly used as shorthand for before anyone else. When used in this way, it refers to a close friend or significant other (e.g., boyfriend or girlfriend) having favor over others. Below are some examples of how this could be used.
I love you, BAE.
I'm going out on a date with my bae tonight.
On Jul 23, 2014, Pharrell Williams posted a music video of his song Come Get It Bae, which is an example of its usage and pronunciation.