Attorney-client privilege isn't a Constitutional right, it's just an evidentiary privilege. And it can be lost by disclosure to third parties. Moreover, you're glossing over the fact that much of the information held by third parties doesn't fit within any conception of "your papers and effects." Even if we assume that your Google Docs are covered, what about information like your facebook friends? Those database records linking you to other facebook users aren't your documents, they're Facebook's.