If you work for a company for a few years and maintain your LinkedIn account, you will build up a set of contacts based on your employment. What happens if those contacts are customers? Do they belong to you or to your employer? That was the issue in Cellular Accessories for Less, Inc. v. Trinitas
So, you have a LInkedin account. As with most users, many of your contacts are co-workers. You leave your employer and send messages to your contacts on Linkedin. Is that a problem? It is a problem, if you have a non-compete with your former employer in which you agreed to not contact former your former