I'm starting to see some Websites offer the option to login via Facebook. I'm curious how useful it is a feature. For example, when someone logs in, does her friend knows on Facebook that she logged in? What if there are more fields that I require than Facebook stores? Which one would you use from the list of 13 controls?http://vatlab.com/facebook-asp-net-libs/facebook-connect-asp-netIt would save me a lot of time to buy the app from them. But I wonder if there is anything else I'm missing out (like a free version elsewhere).My goal is to make registration/sign up quick and painless so they go through the motion while spreading the word. At the end of the process, the user will receive something (i.e. free e-book).So it seems that there are 2 points where Facebook can help and perhaps make their friends take notice. Facebook Connect and Facebook invite friends.
How useful is Facebook Connect Login?
facebook;authentication;registration
Facebook login integration will let you do just about anything you want.  One complaint people have is that it changes pretty often and that you need to invest a decent amount of time in keeping up with it.  If your goal is to stick with Facebook only and use a lot of the more advanced features then there is value in using it.However, if you are looking for an easy solution check out http://www.janrain.com/.  There is a free plan and multiple levels of pay for service plans. They also let you connect to more than 1 login provider (OpenID, Twitter, etc).  If you want to learn about the service checkout This Week in Startups show #73 for an interview with one of the founders.Just to be clear, I don't work for or have any vested interested in Janrain.