When you treat special characters such as underscores, colons, and hyphens as a space, you corrupt my search for a single term into multiple terms, aka not what I sought, so I get too many useless results. Function names, class names, or file names ought to be treated as a single word not several words. Even when I place quotes around them you treat it as two concurrent words not a single word.
Please correct your algorithms or at least give me the option to have your product work correctly. Maybe like Google Book Search you should have Google Code Search? Software is information too.