i was using google adword keyword tool to find low competitive keywords to build micro niche sites,but when i know about MNF i had done some research and i have now a 30 day trial.the local and global search count is same as google adwords keyword tool as it is picking it from there.the advantage i found was the backlink calculation,But my problem is i do not understand what is ad cost means.I know it is the advertisers given amount,I selected an exact match keyword it has 41 ad cost in MNF.But when i am looking at the google adwords traffic estimator it shows the estimated average cpc as zero.what is the difference between these two.please let me know