Recently we got mails from users that can not login to BibSonomy using their Google OpenID. Today we traced at least one of the cases down to a problem with Google's OpenID service.
Y. Song, L. Zhang, и C. Giles. CIKM '08: Proceeding of the 17th ACM conference on Information and knowledge mining, стр. 93--102. New York, NY, USA, ACM, (2008)