tedster - 2:52 am on May 14, 2011 (gmt 0)
Obviously we're not going to be writing unique product descriptions for 200,000 products, so there will be quite a lot of duplicate content.
I'd say put up the non-original descriptions only for your shoppers to browse, but not for Google to index. Use the meta googlebot no-index tag, or x-robots directive or even robots.txt disallow. But if you let Google index a couple hundred thousand duplicate descriptions you will risk destroying the good that you've already built up by getting a site-wide negative quality score.