As you think back to the days when Yahoo was primarily a directory, to DMOZ, and the many other directories of categorized, human edit links over the years, could the case be made that Google received virtually millions of man hours of free help to build their search database?

For a many years, Google encouraged people to submit to directories, and people who did this benefited in the Google search results. Did Google use directory editors as a free way to screen submitters for a long time?