Why No Hits?

I have searched around for studies done on why one day a website can get 20 hits, and the very next day with no addition or extra promotion to their blog they can recieve 2000 hits. This very blog has similar sporadic results day to day.

For instance, my project wonderful ad space on my side bar can sell space for 4 or 5 cents per square some days, and the very next day struggle to have a buyer for 1 cent. As of this exact moment only one of three ad spaces are being sold for a measly 1 cent. This is frustrating.

I understand that selling advertising space, especially on blogs, can be a very up and down market, and its easy to get caught up in the swings. I try hard not to get mad when its low, and not to expect the highs to last very long. The best method, as every says, is to simply avoid checking it until the end of each month. Which, when I can hold myself to that, is very effective.

I have tried very hard to understand my own results...why does my page get a boost on certain days. I can analyze my exact entry links daily and still not find any conclusive evidence as to why one day I recieve a certain number hits, and the next I recieve none.

Does anyone have any evidence as to what is the reason for this constant fluxuation in traffic from one day to the next? Is there a mathmatical formula I am unaware of?

I would love to hear and blog about your thoughts.