Difference between sign up with Facebook/Google/etc and log in with Facebook/Google/etc

Question

I am currently trying to implement Facebook, Google and other third parties connectivity for my web application.

When I browsed many webpages I noticed there are two options, take the Facebook option for example: Log in with Facebook and Sign up with Facebook.

From what I could tell they both do the same thing, if you don't have a user in your database with Facebook retrieved email, the app creates one and logs you into the new account. The same can be said about Google login/signup.

What would be the difference between "Log in with x" and "Sign up with x"?

Answer 1

"Log in with Facebook" implies that you already have an account.

"Sign up with Facebook" means that you will create a new account.

You could have the same button for both, unless perhaps signing up required more info than just you name and email (which Facebook would give you).

Answer 2

Signup is done once for any website, later you need to login by using the same credentials as given earlier (during signup). After a successful signup you are automatically logged in, but during your second visit to the same site, if you choose signup again you may be at loss because of the following reasons:

1. Signup will take more time as there is data that needs to be put into the database and after that you are actually logged in.
2. Redundancy is a factor.

Hence it's better to signup first and if your are signed in the you can log in later.