If you're going to invest in 1,000 articles ($10,000? $5k?) How do you ensure that you're getting your money's worth? Its easy to say that you should know by the 100 articles, but its really not that simple because (a) you need time to see the results from those 100 articles. The results would be different a year or so from the date you release it and (b) the whole thing could blow apart with another Google update or your site getting the ax.
So how do you measure the effectiveness and the ROI of articles these days?