I was also the one who made the "5% a week growth" claim (at the Internet Identity Workshop this week) and unfortunately it was not clearly quoted. "5% a week" describes the growth we are seeing in new relying parties (aka sites-that-support-OpenID). Yes, its impossible for this growth to keep up over time but its still a valid data point. Graph is forthcoming.

I'm shamelessly linking to my own blog here but I think there are a few answers to the questions people are posting on this thread:

* How do I choose a third-party OpenID provider?

* Converting your existing site to OpenID

* How do I use my own domain as my OpenID?

* OpenID and Phishing