"...starting the week of January 11, we’ll remove the ability for people with Twitter, Yahoo, Orkut or other OpenId providers to sign in to Google Friend Connect and follow blogs. At the same time, we’ll remove non-Google Account profiles so you may see a decrease in your blog follower count.
We encourage you to tell affected readers (perhaps via a blog post), that if they use a non-Google Account to follow your blog, they need to sign up for a Google Account, and re-follow your blog. With a Google Account, they’ll get blogs added to their Reading List, making it easier for them to see the latest posts and activity of the blogs they follow.
We know how important followers are to all bloggers, but we believe this change will improve the experience for both you and your readers."
Posted by Michael Goddard, Software Engineer
This has been happening over time. I have lost a lot of followers and couldn't understand why. Now I know. At this point, I don't know what good it does to post this in a blog post when those affected will not be able to see the post. But, I will do as Mr. Goddard suggests and hope for the best.