One of the reasons why you will not see me connecting my Twitter, Facebook, LinkedIn, (enter any other social network) with another application is because in exchange for that specific connection you may be giving away something of value.
We all know that there is a price on being part of a social network, networks provide their service in exchange for your data and the more they convince you to give your personal data the better. That’s why they encourage you often to set reminders, check in, like something, provide your DOB, city, state, and more.
Where I feel networks go beyond harvesting your personal data is when networks harvest data from my friends or family.
If you connect to the Service using credentials from a Third Party Application (as defined in the Terms and Conditions of Use) (e.g., Facebook), you authorise us to collect your authentication information, such as your username and encrypted access credentials. We may also collect other information available on or through your Third Party Application account, including, for example, your name, profile picture, country, hometown, email address, date of birth, gender, friends’ names and profile pictures, and networks.
That may not be scary for you but take a look at what else they can do with your data:
the transfer of your information outside of the country where you live;
the public availability of your information and the controls over such information as described in Sharing information.
There you have it, short and simple. Does that mean that I will stop using Spotify? Personally I won’t stop using the service, I just won’t connect my other social networks.