!!! Overview[1]
[Social Websites] have become the largest [providers of online identity|Identity Provider (IDP)] through the use of [Social Login].


When you use [Facebook] to log into a third party [Website] ([Relying Party]), you are participating in an identity regime that has a particular constitutional order and granting it [legitimacy] by your participation. Further, the [Relying Party] has also chosen to recognize the [legitimacy] of [Social Login].

The constitutional order of [Social Login] is found in the terms and conditions in the [Contract of Adhesion] that [Social Login] [identity providers|Identity Provider (IDP)] impose on people and [relying parties|Relying Party] alike. The system is a "take it or leave it" proposition with terms that can be changed at will by the [Social Login] [identity provider|Identity Provider (IDP)].

A constitutional order makes different promises to those in the system (the users) and those on the outside (the [relying parties|Relying Party]). Let's examine the promise that [Social Login] makes:
* To people [Social Login] says "use the [identity|Digital Identity] we provide to you and we will make logging into sites you visit easy."
* To [relying parties|Relying Party], [Social Login] promises "use the identity we provide and [trust] us to accurately authenticate your users and we will reduce your costs, increase flexibility, and give you more accurate information about your users."


!! More Registrations, More [Customers]
Even if a consumer finds real value in a brand’s offerings, a lengthy [registration] form can overwhelm that perception and send the [Customer] elsewhere in search of a more hassle-free experience. This reality is driving the increased adoption of [Social Login], since signing in socially is a quick and easy two-click process.

Most people find this process more [trustworthy|Trust] than filling out a form, since they retain control of their own [Personally Identifiable Information] and preferences and choose what information they share. [Social Login] also instantaneously enables a more personalized experience, since new [customers] are addressed by name and content can be tailored to their provided interests.

[Social Login] is especially important to implement for [Mobile App]—registration forms are even less appealing on a five inch screen—and delivering an excellent [Mobile App] [User Experience] today is absolutely essential. According to [Gartner], “By 2017, U.S. customers’ mobile engagement behavior will drive mobile commerce revenue in the U.S. to 50% of all U.S. digital commerce revenue.”

!! [Social Login] not Accepted by All
As successful as [Social Login] has been, there are a lot of places that social login has failed to penetrate. By and large, [financial|Financial Organization] and [health care institutions|Health Care Organization], for example, have not joined in to use [Social Login]. Why is this?

A constitutional theorist would say that they've failed the [legitimacy] test. Some [relying parties|Relying Party] and some people (either completely or for some use cases) have failed to yield their [sovereignty] to them. [Legitimacy] ultimately rests on [trust] that the regime can keep its promises. When that [trust] is missing or lost, the regime suffers a legitimacy crisis.

For people, the lack of [trust] in [Social Login] might be from fear of [Identity Correlation], fear of what data will be shared, or lack of [trust] in the [security] of the [Social Login] platform.

For [relying parties|Relying Party], the lack of [trust] may result from the perception that the [identity provider|Identity Provider (IDP)] performs insufficient identity proofing or the fear of outsourcing a critical security function (user [authentication]) to a third party. An additional concern is allowing a third party of have administrative authority for the [relying party's|Relying Party] users—not being in control of a critical piece of infrastructure. That is, they don't [trust] that the rules of the game might change arbitrarily based on the fluctuating business demands of the [identity provider|Identity Provider (IDP)].[2]

These [trust] failings ultimately stem from the structure of the [Trust Framework], the constitutional order, of [Social Login]. Because it's based on terms and conditions imposed by the [identity provider|Identity Provider (IDP)] whose primary business is something else, people and [relying parties|Relying Party] alike have less confidence in the future state of the identity system. So, it's good enough for some purposes, but not all.

!! [Government Entity][3]
[{$pagename}] can also cause difficulties in countries with active censorship regimes, such as China and its "Golden Shield Project," where the [Third-party] [website] may not be actively censored, but is effectively blocked if a user's [Social Login] is blocked.

!! [Social Login] and [Compliance]
WWith the recent [2018|Year 2018] [Facebook] scandal, the [Implementation] of [PSD2] and [GDPR] many [Organizational Entities|Organizational Entity] will not be able to keep up with the [Regulatory compliance] and [Regulatory Burden] making [Social Login] more attractive.

!! If not [{$pagename}] then whom?
* [Financial Organizations]
* [Government Entity]

!! More Information
There might be more information for this subject on one of the following:
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* [#1] - [Self-Sovereign Identity and the Legitimacy of Permissioned Ledgers|http://www.windley.com/archives/2016/09/self-sovereign_identity_and_the_legitimacy_of_permissioned_ledgers.shtml|target='_blank'] - based on information obtained 2016-09-23- 
* [#2] - Note that [identity providers|Identity Provider (IDP)] in the [Social Login] regime are not primarily in the business of providing identity. Their business is something else (mostly selling ads) and [providing identity|Identity Provider (IDP)] for [Social Login] is, from their perspective, part of serving that end. (Taken from Self-Sovereign Identity and the Legitimacy of Permissioned Ledgers)
* [#3] - [Social_login|Wikipedia:Social_login|target='_blank'] - based on information obtained 2018-04-12