I am building 3 new websites and want to use WIF4.5 for SSO across these 3 different domains. I have read tons of materials about the WIF, while I understand the principles and purpose of WIF I am still very confused about how it works in real life, please help me understand the following questions, many thanks.
All my sites will be hosted using shared hosting services.
Everyone is saying that there's no need to build you own STS, but if that's case where can I found external services I can use to sign in my users and what about normal user registration interface for new users? and What about my existing users?
If i only need to build claim based web applications, where do I get user identities from in a real production environment? Do I have to pay them or do they need to go through my sites to approve them?
Is it correct that its no longer possible to let user register on my websites if I use STS?
Do I need to enable SSL and buy X507 certs for all my sites if I want them to be claim based websites?
I want to have a shared user database to store all our users, old and new, does that mean I have to build my own STS?
What exactly does it take to build my own STS, can I pcik one of my websites to be my own STS provider for my own websites?
What does it take and cost to build a STS? like SSL, certs, other stuff?
Can I enable social sign-in like facebook/Google/Yahoo if my sites are claim based?
Thank you guys.