I've been trying to search for this on the Internet, but apparently there are not many links. I was wondering what the paper by Kachru about the 10^100 string vacua suggested really? Does it mean that there are 10^100 different formulations of string theory (formulations just like the original ones such as E8 X E8 or Type IIA)? If this is true, has there been any proposed mechanism to reduce this incredibly large number or rule it out? Just wondering what it meant, because if there are really such a fantasic number of different formulations then wouldn't it seriously pose problems for the theory?