Scoble complains about the lack of a ‘do not follow’ link attribute on Tailrank: link to an article that you are complaining about and the linked article gets a (slightly) higher search rank, and more people read it.
Sure, this is a problem, but the real solution is setting a standard (could be grass roots) for adding optional attributes to HTML links (I wrote about this More on link types and the Semantic Web a few months ago).
Jon Udel has a great idea for combining CSS style ids with semantic information. The microformats people have good ideas for using the rel attribute to specify a relationship to a link (license, help, type-of, friend, etc.)
What I am most interested in is having enough usable information on the web to enable me to write software tools that can automatically extract information on trust relationships between information sources on the web. However, the range of applications is just about infinite – given more metadata.