Presented by JanRain (a major player in the OpenID market since its inception in the year 2005), RPX is a solution that makes life easier for site visitors by enabling them to sign in or register to any website using their preferred service providers.
It can be said that this solution works as a proxy between third party identity providers and the website in question.
An interface is produced whenever the user intends to sign in, and it lets him choose the respective provider. Once one has been selected, RPX carries out an authentication process.
This interface can be either directly embedded into webpages, or added as a popup overlay. Besides, clients can customize the interface the way that they see fit.
There are three different incarnations of RPX available, namely “Basic”, “Plus” and “Pro”. The “Basic” plan comes free of change, while the other ones add some features such as automatic synchronization of social profile data and configuration support.
At the end of the day, RPX simplifies the process of implementing OpenID single sign ins, adding further accessibility to any site on the Internet. Follow the URL that is provided below if you want a taster of this solution for yourself.
RPXNow.com In Their Own Words
“RPX makes it easy to consume OpenID based single-sign-on and its family of protocols on your website.”
Why RPXNow.com It Might Be A Killer
It gives any website an added immediacy and ease of use.
Some Questions About RPXNow.com
How much do the paid plans cost? How can I find out which one will suit me best? 
