I was having the same problem. Finally figured it out. When you get to the blog page, it says at the bottom to either log in or sign up. It wouldn't let me log in with after signing up with Forbes, but..., when I chose "sign up" and used the same info with the Forbes sign up, it sent me an activation link in the e-mail and was finally able to post a comment. (Does that make sense?:icon_scratch:) In other words, sign up again on the blog page.