I've seen this in Wordpress:
I see that this setup would allow for a flexible way to add additional fields to users without modifying the table structure itself.
Is this an ideal way to setup a table for users that may differ in fields if they are a business or individual? Obviously there would be a basic table for the information all users share (like log in information).
A problem that I see is if I wanted to grab tons of users, it could get a little complicated. At best, I would be able to perform 2 queries, 1 for each table. And then using PHP, join the results together..