All bios are personal to a certain extent. In fact, it's almost impossible to write one purely for professional purposes that doesn't contain some personal information -- education, work history, achievements, for example.
Personal bios, on the other hand, generally relegate work or career information to a secondary, supporting role, and focus instead on personal qualities or attributes.
Example of information that is commonly contained in a personal bio includes:
- A brief overview of childhood and/or early experiences.
- Events (not related to work) that have shaped your beliefs and value system.
- Information about family members or mentors who have played a significant role in your life.
- Religious affiliations or personal philosophies.
Good personal bios are truly that - personal. I know I've read a good one when I end up with a clear picture of who you are and what you believe in. Use that as your 'measuring stick' and you can't go wrong.