del.icio.us is currently experimenting  with RSS feed licensing. This is an important issue. Information in an RSS feed should be licensed as one does with the blog posts too. What, if one does not want to have others to use his content commercially? The licensing is there to talk about it. Make a clear statement now and make the users clear, what they are allowed to do with your feed and eventually what they must not. If you choose a Creative Commons license be aware, that they are non-revocable , so consider thoroughly. I have chosen an attribution sharealike license though for my del.icio.us feed. What the del.icio.us license selector for CC licenses IMHO currently is missing of, is a per-jurisdiction selection.