Duplicate LinkedIn profiles are common. This can happen when you create a LinkedIn profile using one address then you receive another LinkedIn invitation to join through a different address. When you click on the link to the LinkedIn website, it does not recognize your email address and you are encouraged to create a profile.
photo credit: Ivan Walsh
Why is this a problem? When you build connections and recommendations they are tied to a single profile. Currently, there is no way to merge two different profiles. They are each stand alone entities independent of one another.
Think of a customer or client who looks for you on LinkedIn. If they see two separate profiles, how will they know which one to connect with? The only way to resolve this is to delete one profile. When you do this, you will lose all your connections and recommendations on the deleted profile.
You can prevent this from occurring by updating your LinkedIn profile with all the email addresses you use.