Danny Sullivan is on a mission to do something about link spam (comment, guest book, trackback, forum, and so on). In a recent entry at the SEW Blog, Danny wrote on the topic of Google To Add "Nofollow" Tagging Of Links To Fight Spam? The proposal is to use the following within your links; <a href="http://www.site.com/page.html" rel="nofollow">Visit My Page</a>
By adding rel="nofollow" it would instruct the search engines to not string along any "vote" "weight" "importance factor" to the page it is linking to.
My thoughts are that the same can be done through JavaScript redirect tags. If the search engines can not find the links, then they will not count. This blog ensures that all comments go through a redirect script, but it does not stop the spammers from spamming this blog. So a simple "nofollow" tag might not do much either. In theory, it makes sense.
Forum discussion at Search Engine Watch.