This is an interesting bit about building anonymity into the internet. Unfortunately this article tends to conflate privacy and anonymity.
When people talk about anonymity the usually fail to distinguish between real anonymity and granted anonymity. For instance my ISP could grant me anonymity using one of the schemes discussed in the article. Or I could pay cash to use an internet café computer. In the former my anonymity only lasts so long as my ISP protects it. It is granted and ephemeral. In the later case my anonymity is real to the extent of my ability not to reveal personal information as I browse.