[adrianhoward]

For me the most important bit in that was the last line.

"Is it worth it? Nope, it’s not to us." (my emphasis)

Not all businesses are the same. B2B businesses like MailChimp usually don't see major increases in value through third party auth. They're providing serious value. People will go to the effort regardless.

With a casual use B2C site removing even the tiniest piece of friction in the login process can mean the difference between a purchase and people just going away.

It depends. This is why we test shit :-)

(Also - unrelated to this - is that the "login" bit is often not where the biggest win for third-part auth is. It's in reducing friction in registration. I've seen high single digit percentage improvements in abandonment of registration for some B2C sites due to getting profile info from twitter/linkedin/etc. cutting the time it takes to setup accounts fully. Lifetime value also increased since profile info was generally better from those sources which was an important part of users getting value out of the system, and so the business getting value out of those users).

[edit: also - they seem to be looking at total numbers, rather than doing any kind of cohort analysis on the folk using twitter/facebook/whatever... which may well lead to different conclusions]

[voyou]

"The "login" bit is often not where the biggest win for third-part auth is. It's in reducing friction in registration."

Yes, which makes it particularly annoying when a website advertizes sign-up via social network only to immediately follow this sign-up with its own registration form, making the social network signup stage an additional stage in signing up, rather than a substitute.