After some recent issues; I'm slowly backing off using Firebase as my "database" and moving back to SQL. I'm sure all the NoSQL fans out there will scream "Why!!!!!!!!!!!!" but I have my reasons and may write a story about how and why but in the interim...

I'm going to disable (previously enabled) logging in with Facebook, Google or Twitter.

I ran a quick query and it would appear, I have about 500 users (ish) that have used one of these services to login.

What is your opinion in how to do this gracefully?

I've come up with so far:

1. Just disable the buttons, if one of these users come to the site, just have them re-register new under the standard login process
2. Email these users of this change and leave it up to them to re-register
3. Write a bit of code, see if one of these users attempts to login with the email address associated with their social network account; send them an email to reset their password and go from there

I feel like option 3 would be a good idea; during the login process, if the password fails (which it will as they never set a password while logging in with their social account), send them an email asking them to reset their password.

Just curious if anyone has any other ideas.