OAUTH seems like a pretty good idea when it comes to helping people authenticate, cuts down on the # of passwords to remember and in general eases the friction of on-boarding. However it would mean that once you compromise one account, you would be able to get into lots of things, all you would need to do is know other sites that used this connection to raise all kinds of havoc.
Do the positives outweigh the negatives when using OAUTH.
In my case I use google as OAUTH for several sites, but my google account is protected with 2 factor auth which many of the other sites don't provide. Does the google 2 factor combined with OAUTH make the other accounts more secure or less secure?
What are the questions I haven't thought of yet in this space?