Entropy of search logs
Qiaozhu Mei, Kenneth Church · 2008
How many pages are there on the Web? 5B? 20B? More? Less? Big bets on clusters in the clouds could be wiped out if a small cache of a few million urls could capture much of the value. Language modeling techniques are applied to MSN's search logs to estimate entropy. The perplexity is surprisingly small: millions, not billions.