I am a major anti-fan of OpenID, but the idea is that these sites will not ask you for your Yahoo/Gmail password. Instead, they will bounce you to Yahoo/Google/

I am a major anti-fan of OpenID, but the idea is that these sites will not ask you for your Yahoo/Gmail password. Instead, they will bounce you to Yahoo/Google/whoever (where it's assumed you'll usually already be logged-in), which will ask you for permission in a standardized, recognizable way. My major objection to OpenID is that it takes a single-site registration/login experience, with one consistent look and feel, and throws two extra HTTP requests and a completely different look and feel into the mix. To me that makes the experience more confusing and inconvenient, not less.