I have read that adding a comments tag to a page will help to be indexed by excite, and a few days ago I updated one of my pages with a comment tag, and to my disbelief I was indexed shortly thereafter by none other than excite.
None of the major search engines read comment tags or use their content in their indexing. Like the other on page factors that have been devalued this is because of keyword stuffing by black hat webmasters.