Hi Alex!

...but also controversial. Moreover, a link to index.php?mode=user could also come from an extern page without rel="nofollow".

Theoretically yes, practically no (at least Google "found" my profile not through an external link). I was quite surprised to see private data (like my birthday) accessible by a net-search.

To be sure the user area won't be indexed you need to set "User area" to "accessible by registered users only".

Would youl please do so here? Thanks.