Well , its a very small trick but useful simpally go to google and search for forum intitle:keyword example--> forum intitle:money and if you keyword is combination of 2 words then forum intitle:money intitle:making like this now simpaly make signatures on them with your links and make new posts on they forums,copy a post from anywhere and paste in that post and may be people will blabber on that post your site may get a nice exposer thru it
You can easily search forums of your subject on google by just searching by the words - forums on or of ----------subjejct. You will get. I got many on my subject.