Breakthrough visits to my site

Two days had a breakthrogh with my site on how to improve brain power. I broke through the 100 visitors per day mark, with 203 visitors! And followed by 209 visitors the next day!
I have to say I am pretty stoked about this. As it was a a radical jump from a 5 day slump, I wanted to know the reason for this sudden boost in visits as before the lull I wouldn’t get more than 50 visitors on any given day. I checked on Rank Tracker which is the program I use to monitor the position my site has for a given keyword. Usually all that comes up is the values for the Google results but now, one of the keyword I target has also obtained rakings on Yahoo and Bing. They weren’t as high as those on Google but it seems to have done the trick.
I have been keeping track of my progress since I launched the site and I will post tge graph soon to ilustrate the correlation between search engine ranking and visits to my site.