When I had a problem with a buyer thinking she was purchasing a sweater instead of the book and I contacted eBay, I was told that i needed to write fuller descriptions and mark each sweater I was describing as just a knitting or crochet pattern! I often write quite long descriptions when describing contents of craft books etc. I don't understand the difference in the 250 character and 800 character options, and I don't know what 'active content' is.
In the spring seller update it gives details for the future limited characters in the description.