Like issues arising in most multiparty content aggregators, whether they're social networks or marketplaces, Etsy's seller situation reduces down to a discovery and reputation problem.

- How do you highlight "genuine" artisan products without some laborious process to inspect the seller?

- How do you allow new sellers to build the requisite reputation to be trusted as good and legit? How do you do this in a way so they don't get drowned out by more established sellers who have been around longer?

- How do you process incoming reviews to prevent voting rings and voting abuse, while nonetheless accumulating information on the seller's performance and trustworthiness?

These are difficult, inexact problems that can't be solved from a book and to the best we know, have to be trial-and-error tuned to the particular community in question. Much more so than anything solely technical, the way these problems are solved end up being the secret sauce behind communities, and similarly often responsible for their decline.