[Dean C]

Not to criticise your modification but I'd say this was a poor way of implementing this. As soon as you put no follow on the links it'll:

1. NOT follow through to that page.
2. NOT count the link in calculating PageRank link popularity scores.
3. NOT count the anchor text in determining what terms the page being linked to is relevant for.

Also your addon will mean google will not try to index the page. Maybe I'm missing something here but why on earth would you not want the search engines to index your page. The only usage for this will be on blog comment pages. Just because a spambot sees your link having rel="no follow" inside of it will not mean it won't spam the email.