OpenID is a great concept. Consolidating your online identity across multiple sites and services is convenient, and arguably offers security benefits. So why do some sites make it such a pain in the butt to use? If you support OpenID on your site, and make it as easy as possible for your users to log in, check out ID Selector.

ID Selector helps you set up a customizable OpenID picker, so your users can quickly get an OpenID or choose one they've already set up. It doesn't require any fiddling with your existing login form, it "just works." The best part is that your users only have to pick an OpenID provider once. When they return afterward, they can just log in with one click. Neat!