NEW YORK (TheStreet) -- The days of the leader as emperor are over. The relationship between employer and employee has changed since the last century. It's a power shift that isn't going to change back.Employees used to be afraid of offending their boss for fear of losing their jobs, which meant loss of personal security and the shame of being out of work. Before the Internet, people basically worked with companies in their region, and the only opportunities they knew about were in the classifieds section of the newspaper and through friends and colleagues. Today, employees know they have rights that employers can't trample on. Employees know that loyalty is typically a one-way street with jobs disappearing as revenue shrinks. The Internet has changed the entire dynamic of the employer/employee relationship. Through job boards such as Monster.com, employees know about opportunities all over the world. Through social networking sites such as LinkedIn, employees can leverage their friends' contacts to open doors and find new opportunities. Employees are starting side businesses to provide a cushion against losing their job or hating their job to the point they want to leave. The stigma of job-hopping has all but gone away. Good employees have more choices because they are good. The question is what a leader needs to do to nourish, lead and retain the best employees.