If you have no-follow links in good number then it can be considered if they have good in number

nofollow forums are useful if they have high PR.

do follow link help in increase page rank Of and no follow link increase traffic on our site.

nofollow is an HTML attribute value used to instruct some search engines that a hyperlink should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing from occurring.

Problem is that many directories and social bookmarking sites are do follow, gain users and reputation and than become no follow.

I think a nofollow link still count if they are from authority site. I'm not sure about that but this is only my opinion.

The Nofollow links will helpful to direct visitors to your website but it won't distribute its page rank to there link partner sites.