But I don't want to hand off my FB, Google, etc to various websites. If a site only offers that, I simply close it and find another part of the web to browse instead.
2. Don't force visitors to use a 3rd-party provider. Always have a local option. As a counter point to (1), many visitors won't want to use their Facebook/Google accounts for authenticating to other sites.
I tend to prefer the oauth options myself... I don't want to have to enter a bunch of information, or add yet another site to lastpass if I can avoid it... Though, if they ask for too much, I tend to just deny and move on...
For example, it's interesting that a site within the past couple of minutes to sign into could use a local account, facebook or google... I clicked fb first, they wanted contact info and my full friends list... google, just my email... so I let it in with my google account.
I think it really depends... I wouldn't offer social logins without also having a local option, but it really depends on your audience.
But it requires you to have an account with some other party, such as Facebook or Google. What if you don't want that? Suddenly this service that you do want to use becomes unusable.
And it also tells Facebook / Google etc what other sites you use, which is none of their business (not that they won't grab that info because of like buttons, analytics, embedded fonts or hosted JS but that's another matter).
Can't have your cake and eat it too. If you complain that you don't want to have to log into sites, it makes less sense to complain when there are ways to have unified logins so that's not necessary anymore.
