Penguin 2.0 update has downgraded the significance of backlinks for SEO particularly if its not relevent to your website content otherwise its good practice to increase quality traffic which in turn augments your ranking for specific keywords.
I Don't Know . actually After Google Upates , i am not able to say that forum Anchor text also Useful For Keywords Ranking ? sometimes i feel it is good For Ranking but i want to know only Dofollow Anchor Text is good or Nofollow is also Good For Keywords Ranking ?
they have value, you just need to link build from multiple resources to create a natural diversity... you also need to vary yout anchor text, more just the url, and random stuff and no more than 10% for your actual keyword, that way you stay out of trouble..!