[dexen]

While it may be argued that `the obscure stuff' is harder to find or may be more valuable/important, I'd disagree with you.

First, the bulk of the search seems to be for the usual stuff. Thus the bulk of revenue from ads for the provider and _perhaps_ the bulk of added value for the users stems from searching for the usual stuff.

Second, as the obscure stuff oft uses uncommon terminology and names, it's technically easier to search for it and display relevant results. The trick is to give useful results for the most common things. Consider how hard it may be to automate (!) picking sensible results for words like `the' or `free'. Or for dates that are represented in one zillions of formats. Of course various approaches (like lists of & criteria for stopwords) have been implemented.