I was ranked in the top 10 for a niche keyword. I accidently did a xrumer blast and left my website under "Homepage" (because I did moodle profile blast which needed it). I blasted a lot of forums with my Web 2.0 backlinks and the profile homepage was still in there. I didn't realize it till there were 79000 profiles made. My ranked dropped to #30-40, and it stayed there for a few days. Now it's not in the top 100... for alot of the keywords.