Here's my current situation: I have a product launch website where I promote new software and get the commission as people buy them. I have SEO some easy stuff before and the result is not bad, average kw will be on page 2-3 while easy kw can be ranked to page 1 (my personal best is top 4) The problem is, when I choose a hot product to SEO, the kw is more difficult too. When I first post my article, it was on page 8, then I get it to page 6 for one day. After that it slowly went down no matter how hard I try, now it's out of top 100 already. I usually create backlink manually. Most of tier 1 are website 2.0, blog; tier 2 is social network, document share; tier 3 is forum signature. I checked the content to make sure all of them are unique and I didn't spam backlink or keyword. I understand the fact that high difficult kw is hard to SEO, but my article was start at a good rank and slowly move downward, it's strange. Please help me.