Top screenshot is from a regular instance of Firefox where I’m returning to LinkedIn after having signed out before. Bottom screenshot is from a private browsing session -- no cookies saved, so I guess I look like a new user to them.
The frustration emerged when I didn’t realize I was in a private browsing session and clicked the big blue button to sign in.
The big blue button on the right is apparently not always the “sign in” button. It is the “this is the button we want you to click” button.
My guess is they want the primary button to always be on the right side. For a first time visitor that primary action is always to create an account. If the user is a return visitor, they assume the user already has an account and so they want the primary action to be to login to that account.
I take it some UX-er got paid handsomely, but I think all it does is confuse people. As someone suggested already, I’d just go for login/register and make login primary (since you only register once, and login maybe hundreds of times after that)
Okay, yeah, what confuses me most is why they used different labels. If I had to take a guess (gun to my head), I’d say one is an earlier version that got stuck in some cache somewhere.