Hi Alfie,

At least all links to 'index.php?mode=user' must be extended by rel="nofollow". It's quite common in other forums and also standard in Wikipedia to use this method for all external links too.

...but also controversial. Moreover, a link to index.php?mode=user could also come from an extern page without rel="nofollow". To be sure the user area won't be indexed you need to set "User area" to "accessible by registered users only".

Alex