This is all about using search engines more effectively, also finding specific phrases, as well as excluding what you don't want.
Google's PageRank technology helps people find the most relevant information on a subject. This is good for basic fact-checking, as the most authoritative sources usually have very high PageRanks, because they are quoted and linked to by others extensively.
However, if you're looking for an obscure message posting by a government official, it's unlikely to be listed very high in the search results unless you're very specific with the keywords you use.
Juicy material that could lead to a scoop is unlikely to have a high PageRank, and if it does, is it really a scoop?