I am 99% sure that's a penalty. Massive drop in unique visitors since the 27th (record for fewest numbers in fact) and out of the 15 or so keywords previously in the top 30, all but one are gone (the one remaining keyword is still #1 in Google, Yahoo, and Bing).
I showed this to my friend and he said that if I was penalized, ALL of my keywords would be gone. However, the fact that one keyword still remains in the SERP and is still #1 tells him that it's a dance.
Which one is right?
Keep in mind though that I've been tracking this site since June or July 2011 and it always had around 300 unique visitors per day. But since the 27th, I've been averaging like 55 UVs/day.
I was about to delete this whole site 20 minutes ago but my friend got me thinking.
Any thoughts, please?