Cheers,
after seeing Stack Overflow's excellent implementation of OpenID, and after seeing what great job Google did with OpenID, I implemented it on a web app I'm working on. During my research I ran into Plaxo as another great RP.
Recently, Facebook added some rudimentary OpenID support. It's apparently used for completely different purposes that ordinarily: I didn't find a way to log in with OpenID there. Yet, there's one thing that caught my attention: on Google-hosted UI, they had a Facebook logo, and a bit different heading. At first I thought this might be because of the new "popup extension" recently designed precisely because of Facebook. However I edited the authorization URL and removed reference to the popup extension, and the icon was still there. When I wrote the extension support, it didn't add the icon.
I looked around, and Plaxo's got their icon on Google's auth page as well.
Although this might be a result of business deal between Google and Plaxo, and Google and Facebook, it might not be the case. So I am wondering: Does anyone have idea how to add this icon?
n.b. I've inquired about this on Google's Federated Login API group, and received no response. I've also repeatedly did searching on the internet; apparently there isn't many people who noticed this and who are sufficiently interested in this.
Google has a white list of RPs that it's doing experimental extra features with. I don't think placing the logo on Google's login page is offered generally yet.