Previously, I did the blog comment job myself. As I didn't have much time, I made it just about 10-30 comments per days and did it for just a few days. And it worked. My site jump from 2nd to the 1st page for the keyword. Latter, I have someone else done the comment for another keyword, and as she do it all days, she she made about 80 links per days and kept doing this for about 1 week. The result is nothing change to the position at all. In some case, it even drop. They're the same site, just different pages and keywords So I wonder if building links fast or slow does really matter. Are there any possible factors for this case?