Also another thing to keep in mind is that some companies want to attain the Profile data from its users. They use this data for marketing practices and understanding target audiences. Data points like Name, DOB, Location etc. Each Social platform delivers a variety of different profile data to the platform owner. The main one being Facebook.
Facebook profile data is a lot more extensive than other Social platforms. You can find a list of the available data points here.
Twitter's profile data comes in a second with most of it focusing on activity within their platform other than their users. See their data points here.
Google's API returns various profile data points and the can be found on their developers.google website.
Hope this helps.