Since adding rpxnow to our website, less users are signing in.
Are these readers worried about giving their (eg hotmail) password to a third party site?
Has anyone found a good way to promote use of rpxnow (or other openid managers) as a secure method of authentication to non tech savvy readers?
Yes there are a number of ways to promote third party login. Universal Music Group and the LA Times have good implementations that pre-message to site visitors how easy it is to login using existing accounts at Yahoo, Google, Facebook, Twitter, AOL, etc.
John Beutler at Janrain can give you some advice: johnb at janrain.com