Funny this should show up, since I am just in the planning stage of implementing common lisps "tagbody" in scheme. It is mentioned in the article, but not really explained. It is a neat little localised goto that is explicit. You can only jump withinthe tagbody.

Why is this useful? Well, goto is a nice little primitive for some things. Tagbody is used in CL to implement the iter (and maybe loop) macro. Because sometimes all you want is unconditional jumping around :)