It's a good idea that we first discuss some fundamentals, as there are many methods and variables that will affect how vendors will ultimately be able to offer these services.
Wikipedia defines API as, "In computer programming, an application programming interface (API) specifies how some software components should interact with each other". For our purposes, an API is coding that is provided by one vendor application (for example, LinkedIn) that can be used by another vendor's program (for example, your SCRM) in order to create the connection that will allow the two different software components (LinkedIn and your SCRM) to interact with each other.
An API might provide access points to some parts of that program but not to other parts. In the case of LinkedIn, at present, it will allow other programs to see your first-degree connections but not your second and third-degree connections.
Your SCRM will also provide its own API for third-party...